Casey is placed in a dangerous situation while working undercover to bring down a trafficking ring being run out of Nesbitt's club. The squad's high turnover rate results in an unwelcome surprise for Severide. Dawson recognizes that her life is about to change. A new candidate makes an unusual first impression. Residents band together to protest a drug den in their neighborhood.

Boden's job is on the line pending an internal investigation. Severide adjusts to Patterson, his new commanding officer. Dawson shakes things up at the work. Casey searches for important evidence in his investigation of Nesbitt. Herrmann tries to keep the peace with Molly's new neighbors.

Evidence that seems to exonerate Boden may not be enough. Brett and Chili find themselves in a precarious situation. The team responds to a stuck elevator in a hotel. Jimmy Borrelli's older brother wants him transferred to a different house.

The squad members come together to support one of their own. Herrmann tries to figure out how to reopen Molly's after it gets shut down. Severide digs deep into the arson investigation.

Boden offers to host a wedding at the firehouse after a fire destroys the original location, but it doesn't sit well with Chief Riddle, who also butts heads with Dawson over her ability to perform. Severide fights for his old position. Capt. Patterson finds himself torn between leadership and his colleagues.

Boden's new neighbor asks him for a favor that could have serious repercussions. Severide is upset when he's treated like a candidate by Patterson. Cruz is visited by a gangbanger who knows his brother. The team responds to a call that involves an 18-wheeler; and is thanked with tickets to see Rush.

Boden suspects his neighbor is setting him up; Severide, who's still on probation, receives a surprise visit from his father and also learns something about Patterson that could be a game changer. Romance blossoms at a fire department gala.

Boden believes Maddox is behind Serena's accusations. Severide reaches out to Jamie, who's Maddox's lawyer, in an attempt to help. Patterson questions whether Boden can remain chief. Brett and Chili suspect that a man passed out in a garden is connected to a previous call. Otis has problems with his social calendar.

Patterson fills in for Boden, who's trying to clear his name. Severide learns where Serena may be hiding. Herrmann and Otis give Freddie a job that keeps him close by. Jimmy and Chili draw more attention then either bargained for.

Herrmann fights for his life after being stabbed; Cruz hits the streets to find Freddie. Mouch proposes to Trudy.

The crossover continues on Chicago Med S01E05 Malignant (II) and Chicago P.D. S03E10 Now I'm God (III).

A tornado threatens Chicago. Chili makes a major mistake, which causes Brett to report her to Boden. Otis asks Dawson to help him solve his women troubles. Severide assists a Department of Homeland Security agent.

Freddie's father begs Herrmann to forgive his son's assault. Casey discovers that a makeshift shelter housing people displaced by the tornado may close. Casey attends a fund-raiser at the request of an alderman. Dawson and Brett experience repercussions after telling Boden about Chili's erratic behavior.

The team responds to a mass shooting; Casey investigates the missing money from the fund-raiser. Jimmy agrees to represent the firehouse in a boxing match against the Chicago PD's 21st District. Chili's behavior continues to be an issue for Brett.

Severide confronts Chili about her erratic behavior. Members of the firehouse rally around Casey, who they think would make a great candidate for alderman. Jimmy squares off against Antonio in the first annual "Battle of the Badges" boxing match.

The team responds to a suspicious call from a neighboring firehouse; and welcomes a new firefighter, though her addition has repercussions. Casey moves forward in his run for alderman.

Casey reconsiders his run for alderman after he's targeted by a propaganda campaign. The squad responds when a man is trapped inside of a burning car. Trudy's nerdy brother plans Mouch's bachelor party. Jimmy and Brett investigate a kidnapping on their own.

Severide and Cruz find a child's remains inside a chimney while investigating a possible carbon monoxide leak inside a home. In other events, Casey braces for the worst in his run for alderman while Alderman Becks continues to bad mouth him to the press.

Sylvie witnesses a murder and is threatened by the shooter not to go to the police. Firehouse 51 jumps into action when a fire breaks out at a restaurant and traps several people inside a vault. Mouch starts to get cold feet.

Casey steps up to help a teenager being bullied by a gang; Severide bonds with a detective’s son after her life is threatened; and Kidd and Herrmann go head-to-head in a test of bar knowledge.

Firehouse 51 unites to help a young boy in tragic circumstances. A high-powered political consultant helps Casey navigate a potential scandal. Cruz makes a mistake that nearly costs him his life.

Dawson saves a young boy from an apartment fire. Kidd's idea for Molly's doesn't go as hoped. Severide hits a wall while advocating for new fire masks. Cruz and Brett utilize a secret weapon to get Otis to see Dr. Halstead take a blood test.

The team responds to a building collapse that's trapped more than a dozen people. Dawson's quest to foster Louie is aided by a familiar face. Otis, who's on medical leave, meets his temporary replacement. Severide and Kidd continue to see each other. Casey is at odds with Antonio.

Boden and Jimmy are at odds. Kidd deals with her unstable ex. Dawson continues her quest to foster Louie. Casey's new political consultant urges him to think big. The team responds to a dangerous structure fire.

Severide and Stella search for Grant, who's AWOL from Chicago Med. Dawson questions her career path. Casey's relationship with his political consultant cools. Borrelli's anger at Boden over his brother's death boils over. Mouch and Brett partner on a new venture.

Casey and Dawson find themselves in the midst a potential political mess. Stella has to make a big decision about her ex-beau. The squad responds to an auto accident. Severide befriends a socialite. Brett and Mouch set aside their writing differences for the greater good.

Casey seeks help with a personal matter from Susan Weller. A rich party guy wants Severide to travel with him. Stella tries to help a sick street kid. Otis and Herrmann share their concerns about Molly's lack of customers.

Lt. Casey finds himself in a bad spot when a forklift accidentally pierces a tank storing acid. Casey is forced to use extreme measures to help a father and daughter in peril. Dawson and Brett respond to an elderly woman who has a difficult senior advocate. Mouch and Brett continue with their secret project. Otis shares some exciting news as he prepares himself for an unusual expedition.

Lt. Casey is unable to rescue a woman who becomes trapped inside her burning greystone, prompting him and Lt. Severide to butt heads over the husband's role in the tragedy. Herrmann is on a mission to catch a mystery tagger that keeps targeting their firehouse and Boden gets a surprise visitor. Meanwhile, Dawson and Brett respond to a 16-year-old boy who was injured during a romantic homecoming proposal.

While responding to a call in the field, Dawson accidentally hits a pedestrian who stepped in front of the ambulance, and is left to deal with the repercussions. Lt. Casey and Lt. Severide disagree and continue to investigate an arson case while Chief Boden is left to decide whether to attend an important function in New York. Elsewhere, in hopes of preparing him for a possible promotion, Lt. Casey puts Herrmann at the helm for a shift so he can discover firsthand what his superiors deal with.

It's a family reunion when Dawson and Antonio's mother and father come to Chicago for their big anniversary party, but things quickly turn south. When a deep secret comes to the surface involving his stepson James, Chief Boden decides to take matters into his own hands. Meanwhile, Casey tries to save a young boy during a harrowing call to a warehouse and Otis and Kidd become competitive at the mud-hundred race.

Lt. Casey and Dawson apply for permanent adoption of Louie, but quickly discover a hurdle. Firefighter-turned-medical student Jeff Clarke approaches Lt. Severide with an interesting proposition. With hopes of reinvigorating business at the bar, Otis convinces a skeptical Herrmann to throw a bash in celebration of the milestone 100th anniversary of Molly's, but not without complications.

Dawson and Casey deal with legal matters in hopes of remaining Louie's legal guardians. Severide continues in his efforts for a bone marrow procedure to help Anna, but when things don't go as planned, he finds himself slipping back into old habits. Meanwhile, Brett opens up to Dawson and members of Firehouse 51 become competitive, much to the dismay of Chief Boden.

The crossover continues on Chicago P.D. S04E09 Don't Bury This Case (II).

Severide agrees to a bone marrow donation but a work accident throws everything into flux. Casey and Dawson try to find harmony at home. Meanwhile, Otis and Mouch decide to film a PSA encouraging people to join the Chicago Fire Department but hit a creative wall in the process.

Dawson finds it hard to keep her emotions in check during an ambo run involving a pregnant teen. Elsewhere, the firehouse is called to the site of a building fire and Casey is forced to make a split-second decision when two victims are each need of life-saving assistance. In the aftermath, Casey is left to deal with the repercussions. Meanwhile, Severide shares a bond with Anna, as she makes her recovery.

The team is on high alert when a previous incident during a fire call leaves a dangerous man on the loose with a vendetta to target Lt. Casey and Firehouse 51, and prompts CPD to step in. Dennis Mack, a buddy firefighter of Severide's father, comes to town to shadow the squad but may have ulterior motives. Meanwhile, Brett and Antonio's relationship hits some bumps in the road when his ex-wife Laura surfaces and Casey has a present for Dawson.

When truck and squad are summoned to the scene of a dangerous accident, Chief Boden makes a split-second decision that overrides Chief Anderson, the incident commander whose house was the first to respond to the call. Feeling his authority was undercut and his reputation damaged, Anderson uses his power to make things miserable for Boden and all of House 51 feels the repercussions.

After exercising his disdain and authority over Chief Boden, Chief Anderson reassigns members of 51 to various houses around town, citing the need for improvement. The ramifications are felt by the crew, who are left to make the best of their respective situations in their new surroundings.

Truck and squad are called to aid in a massive all-city response when an old, ill-equipped factory-turned live/work space quickly turns into a firestorm, trapping countless unsuspecting victims. The dire situation quickly turns personal when it is discovered that one of Chicago PD's own has a family member at the scene.

The crossover continues on Chicago P.D. S04E016 Emotional Proximity (II) and Chicago Justice S01E01 Fake (III).

When a turf war escalates, members of truck and squad find themselves caught in the middle as unsuspecting hostages when a group of armed gang members take cover and assume control over Firehouse 51.

When similar car accidents uncover the fact that someone may be targeting innocent people, a determined Dawson takes matters into her own hands to help push things along. Severide does everything he can to make Anna feel welcome in her new Chicago surroundings. Herrmann, Kidd and Dawson decide to have Molly's included as a stop in this year's pub crawl. Meanwhile, Casey tends to his Alderman's duties when a persistent constituent asks for his help in resolving an issue.

Casey discovers a new crack house on the block that is harboring a female junkie. Dawson and Brett get assigned a new trainee for the shift. Meanwhile, Severide gets an unexpected visit from his father and Herrmann deals with family issues when his son gets into trouble at school.

When the squad's rig breaks down in the field, Casey reunites with his old friend and colleague Jason Kannell from Squad 6. Dawson and Brett serve their time in retraining. Severide tries to remedy what is going on with Anna and finds support from unlikely sources. As Connie returns from her family engagement, the crew lays bets on how long her temporary replacement Marcy will last.

Casey goes to drastic measures to help his friend Kannell. Lt. Severide helps an old widow come to terms with letting go, but realizes he may be the one needing help. Otis and Cruz deal with surprises when they find a new roommate to move in. Dawson and Brett get crafty to save a young girl.

Cruz finds himself in a bad spot when an off-duty incident begins to unravel, prompting Mouch to step in and offer help in hopes of avoiding serious consequences from the CFD. Casey goes head to head with a big politician to get his measure for first responders passed. Lt. Severide makes life difficult for newest team member Jason Kannell and Dawson gets an unexpected visit from her father.

A dangerous warehouse fire puts truck and squad at risk. Tensions are high for Dawson and Casey when Dawson's father overstays his welcome at their home. Meanwhile, Casey continues to fight for his first responders bill, Mouch makes a serious decision regarding his future and Herrmann goes to tremendous lengths to make a young boy smile.

With most of the squad still trapped inside the burning warehouse fire, Chief Boden makes a risky last-minute decision in an effort to save his men. Dawson continues to deal with her father, who has new plans for himself. Brett's childhood friend Hope visits the Windy City and strikes the attention of someone within the firehouse, while Kidd goes head-to-head with her landlord. Meanwhile, a fire at a high school hits close to home for Boden.

After learning the school fire wasn't an accident, Chief Boden turns up the pressure on Severide and Casey to investigate the cause of the fire that trapped his wife. Fueled by a competitive bet against Firehouse 87, Mouch pushes all of the wrong buttons in his need to win the competitive challenge known as the firefighter muster. Meanwhile, as Kidd settles into her new living arrangement, her unresolved feelings prompt her to question the intentions of newcomer Hope.

Lt. Casey gets off on the wrong foot with Sam Mullins, a temporary Chief who is filling in for Boden at House 51 for the morning. When Casey later makes a risky move in an attempt to save a distraught man from jumping off a building, Mullins has a surprise that Casey does not expect. Mouch flies in Cruz's brother Leon as a birthday surprise, but the rest of the squad struggles to keep it a secret. Meanwhile, Brett is caught off guard when she learns new information about her hometown friend Hope.

While running a secret errand, Dawson finds herself trapped in a collapsed parking structure. With all paths of exit blocked, she is forced to improvise and works double-duty to keep a number of injured individuals alive while trying to maintain peace among those trapped. Meanwhile, pressure is mounting on Casey as he begins to take on additional duties, Kidd grows increasingly skeptical of Hope after learning about rumors circulating and the firehouse receives a surprise visitor.

Casey and Severide find themselves at odds after Casey argues with him over the best way to save a teenager entangled in barbed wire. When Casey looks to Boden for help smoothing out the situation, he comes to the realization that he will have to fix it himself. Elsewhere, Otis tries to convince Casey to participate in the beta test for an expensive piece of new firefighting equipment imported from Japan. Meanwhile, Kidd and Hope come to blows over a payroll issue and Brett goes on a date with a doctor she meets during an ambo call.

After heroically saving a mother and newborn baby from a rooftop fire, Kidd receives surprising news when she discovers she is being transferred out of the firehouse. Severide and Casey believe something is off about the turn of events, prompting them to investigate the situation. Otis and Herrmann discuss the possibilities of taking over a rundown bar and Dawson's frustration with her father, Ramon, reaches a boiling point.

Brett attempts to make a lifesaving decision in the field to someone near and dear to the firehouse family. In an effort to impress Lily, Otis scrambles to get everything together for the grand opening of Molly's North. Meanwhile, Boden becomes emotional following the rescue of a famous blues player from a burning apartment building and Dawson struggles to come to terms with how she has been dealing with her father.

After saving a young girl, Dawson is forced to make a tough decision when she finds out the girl's father is addicted to painkillers. Herrmann loses his cool and gets into an altercation with a police officer after responding to a call. Otis and Cruz are on a mission to find out who Brett is dating. Meanwhile, Boden is skeptical when Donna's brother Julian unexpectedly comes to town.

After learning unsettling news, Dawson enlists Severide to help her out. Elsewhere, Casey and Dawson struggle with communication issues while Brett and Kidd compete to win the heart of Zach, a Hazmat officer. Meanwhile, Otis, Herrmann and Mouch are on a mission to locate the source of a horrible stench that is making life unpleasant at Firehouse 51.

Dawson and Casey do everything they can to locate Bria's whereabouts after discovering important new information. Lt. Severide reunites with Chief Grissom, and old family friend. Meanwhile, Cruz enlists the help of Brett and Mouch to create a new tool and Kidd and Zach go on a date.

After responding to a time-sensitive rescue, Casey and Severide don't see eye to eye on the best course of action. Herrmann struggles to entertain his daughter on "bring your child to work day." Brett is joined by a surprise guest during a spa getaway, courtesy of Dawson, while Kidd's social life gets a boost.

After photos of Casey and Severide jumping off the roof during a heroic rescue make the front page of the newspaper, Boden unwillingly agrees for the photographer to chronicle a day-in-the-life story at the Firehouse. Dawson and Brett are on a mission to find out what keeps happening to Gerald, a frequent flier they know who lives on the streets. Meanwhile, Herrmann decides to take up life-coaching as a side job and Kidd makes a decision regarding her living arrangement with Severide.

While working to track down a bombing suspect, Voight and Antonio meet with Chief Boden, who unwillingly agrees to let Dawson and Brett go undercover. As the investigation continues, Boden, Casey and Severide lend their skilled expertise in the investigation. Elsewhere, Kidd and Zach's relationship hits a bump and Cruz has a hard time expressing his true feelings for Brett. Meanwhile, Herrmann and Connie are forced to come up with an alternative solution when two birthday parties are booked on the same day at the firehouse.

The crossover starts on Chicago Fire S05E016 Profiles (I).

After responding to a car accident, Casey and Dawson become skeptical when a domineering husband continues to answer for his injured wife. Cruz becomes frustrated with Herrmann and Mouch when he discovers they have contacted people regarding his "Slamigan" invention without his knowledge. Kidd uncovers something meaningful and important to Severide while Brett discovers some potentially unsettling news.

In response to a call involving a residential fire, Otis and Kidd's lives are suddenly put in jeopardy when gunfire goes off inside the house. Dawson comforts Brett during an especially trying time. Meanwhile, Casey begins to notice that romance might be going on within the firehouse.

The crew struggles to come to terms with an injury to one of their own; a temporary replacement must be dealt with; Boden ponders some interesting news; Kidd has a hard time keeping a secret.

Boden has a lapse in judgment in the aftermath of rescuing a young boy. Kidd struggles to win the approval of Severide's mom after a surprise visit and Otis takes on new responsibilities at the firehouse.

When the FBI takes over Firehouse 51 for an undercover mission, Casey and Severide volunteer to assist with the investigation. Kidd attempts to help Severide come to terms with recent developments he's been managing.

After responding to a residential fire at a property belonging to a Mexican drug cartel, Casey is skeptical of Cordova after a hefty amount of money was found missing from the crime scene. Elsewhere, Kidd makes a big decision.

After saving a girl from a car accident, Chief Boden and Lt. Severide are taken aback when they receive a surprise package. Brett struggles to keep quiet about Cruz reacquainting with his now-married high school sweetheart and Otis tackles his next challenge. A crisis brings Bria back into Dawson's life.

Lt. Severide is shocked when Rene Royce resurfaces; Casey comes up with a plan to help Chief Boden in his latest pursuit; Kidd regrets a decision she made regarding Severide; Herrmann clashes with Lt. Colannino over their son's basketball team.

Boden takes a big step in the pursuit of a major career decision. Kidd becomes increasingly distrustful of Renee's motives with Severide. Herrmann has trouble bouncing back after a tragedy.

Boden's chances for a promotion are met with potential complications. Dawson and Casey don't see eye to eye on an important decision, while Kidd finds herself struggling to find time with Severide. Brett and Dawson respond to a tough call that quickly turns dangerous.

Casey tries to deal with his unsettled personal life and the firehouse welcomes a new member. Boden clashes with new Assistant Deputy Commissioner Jerry Gorsch.

Firehouse 51 is faced with a daunting challenge when an out-of-control blaze consumes a 15-story apartment complex, trapping victims on the top floors. Complicating the rapidly escalating situation, members soon discover that someone close to home may be one of the trapped victims.

The crossover continues on Chicago Med S04E02 When to Let Go (II) and Chicago P.D. S06E02 Endings (III).

Chief Boden becomes increasingly skeptical of Assistant Deputy Commissioner Gorsch's motives, while Severide gets wrapped up in a difficult situation following the rescue of a child from a car wreck. Trying to fit in with the rest of the firehouse, Foster is tasked with doling out some personal advice to Cruz.

Firehouse 51 is on high alert when a series of explosions rock the city. Herrmann adjusts to his new duties and Kidd gets a visit from an old friend.

Working alongside a journalist, Casey does some digging into the cause of a trailer park fire. Boden hits his breaking point while Mouch, Herrmann and Cruz work to figure out why Molly's isn't performing up to expectations.

Halloween is in full effect for Foster and Brett, who are summoned to a home where a prank has quickly turned serious. Gorsch continues his reign of terror on Firehouse 51.

Severide faces some major adversity and Kidd is on a mission to help in any way she can. Following a car accident rescue involving a teenage girl and her young sister, a suspicious Brett has an unsettling feeling there is more to the story than what appears on the surface.

Firehouse 51 is called in to battle a dangerous structure fire that places everyone in peril. Severide makes a big personal realization. Casey lends another helping hand to Naomi, the investigative reporter.

Stakes are high when a massive car pile-up on the freeway impacts someone dear to the firehouse family. Brett and Foster encounter a harrowing call while Kidd and Severide find their relationship being tested.

A dangerous situation leaves Casey and Naomi in peril. Foster and Brett are in charge of planning a field trip visit to the station while Severide and Kidd go through tough times.

Foster faces blowback after pointing out a doctor's oversight. Brett helps Casey look for a new apartment. Kidd prepares Tuesday the Dalmatian for the Fire Safety Dog Competition. A serious accusation is leveled against Severide.

When the firehouse is called to a motorcycle crash, Casey and Severide sense that the details don't add up and work to determine exactly what transpired. A rift develops between Mouch and Otis. Brett, Foster and Kidd work to secretly fix a dent in the ambulance bumper they believe they unknowingly caused.

Cruz leads the charge in getting the firehouse to gear up for the Polar Plunge. Herrmann has a hard time bouncing back after dealing with a tough call. Foster's personal relationships begin to interfere with her job.

Brett, Foster and Kidd take a road trip to Indiana and encounter an accident involving a boys' hockey team that leaves them scrambling and relying on their instincts to save the injured. The rest of Firehouse 51 competes in the annual chili cook-off.

A spate of robberies comes to light after a firehouse lockbox key goes missing; Sergeant Hank Voight suspects a firefighter may be involved, and with Boden's support, he recruits Cruz to go undercover to help sniff out any suspicious activity.

The crossover continues on Chicago P.D. S06E15 Good Men (II).

Casey struggles after experiencing a narrow miss on a call. Otis wins a unique sporting opportunity in a raffle. Grissom turns to Severide for assistance when the mayor's office sends a task force to Firehouse 51.

Tensions run high between Casey and Herrmann after the firehouse responds to an apartment complex fire. After discovering something extremely suspicious during the call, Kidd and Severide do some investigating and get CPD on the case.

Severide gets angry at Cruz when he feels his orders were disobeyed in the field. Boden reconnects with an old high school friend during a call to a house fire. Herrmann has issues when one of his favorite knick-knacks from Molly's goes missing.

A horrible storm wreaks havoc on Chicago and impacts Firehouse 51 when the power goes off. A little boy mysteriously shows up at the station and everyone works together to uncover who he belongs to. Foster and Kidd argue about Severide.

Severide and Boden search to uncover whether arson was the cause of a fire at a hair salon. Mouch, Herrmann, Otis and Kidd make a startling discovery in tracking down the missing piercing nozzle from Engine 27.

A serial arsonist cold case is reopened when Lt. Severide finds a connection to a recent salon fire. Firehouse 51 celebrates a retirement party.

Severide and Kidd continue to investigate Benny’s old arson case, unexpected news leads Brett to ponder a big decision and all hell breaks loose.

The mattress factory fire spirals out of control. Truck and squad lay it on the line in hopes of getting the trapped victims out alive.

Lt. Casey struggles to get Chief Boden to sign off on an energetic new recruit. Against her better judgment, Foster extends an olive branch to her irritating new medic. Otis inspires Herrmann to seek new partners at Molly’s. Brett realizes life in Fowlerton will take some getting used to.

Brett and Foster question the suspicious circumstances surrounding a brutal attack at a juvenile detention center, which leaves them searching for the truth. A convoluted new technology installed inside Firehouse 51 tests everybody’s patience. Kidd gets chosen to represent the district at a leadership conference.

A rare but deadly bacteria takes its toll on numerous victims around the city, leaving Chicago’s finest first responders to work together alongside the CDC to resolve the dangerous situation. Following a fire at a local university that ties into the outbreak, Severide has suspicions that something bigger is happening.

The crossover continues on Chicago Med S05E04 Infection, Part II (II) and Chicago P.D. S07S04 Infection, Part III (III).

Kidd must prove herself at the National Firefighter Leadership Conference while the rest of Firehouse 51 is called to two eerily similar car wrecks. Mouch tries to keep everyone in the firehouse informed by starting a newsletter, but things quickly get out of hand. Cruz deals with a heartbreak.

Cruz and Severide suspect foul play when a fire started by an elderly woman turns deadly. Kidd, Foster and Brett create a women’s-only lounge. Firehouse 51 celebrates some good news.

Severide must make a tough decision about the future of his career at Firehouse 51. Herrmann deals with the consequences of his temper. Cruz is excited to demonstrate the Slamigan at the Firefighting Expo. Commissioner Grissom returns.

Severide begins his assignment at the Office of Fire Investigation and gets off on the wrong foot when, despite his orders, he reopens an old case. When the cause of an apartment fire hits close to home, Herrmann is on a mission to get to the bottom of it. Kidd finds herself burning the candle at both ends.

An unexpected visit throws Casey for a loop. Severide sets out to exonerate a wrongly convicted arsonist. Kidd pays the price for burning the candle at both ends. Cruz goes on a mission to fix one of Otis’s old toys.

Members of Firehouse 51 are dismayed to learn their boundaries have been redrawn to overlap with an adjacent station and problems quickly arise. Casey and Gallo hunt a missing piece of equipment. Brett and Foster find themselves at odds. Mouch tries the find the recipient of a mysterious letter he discovers.

A pest control problem forces the 51 team to temporarily bunk with Firehouse 20. All under the same roof, Casey clashes with Capt. Delaney while Foster, Kidd and Brett fear Capt. Leone has it out for them. Boden mulls a procedural overhaul.

A series of false alarms at a private school hinders the firehouse's ability to respond to legitimate emergency calls. Kidd asks for ideas to surprise Severide on his birthday. Cruz and Brett rent out their extra room, but the new tenant is more than they bargained for.

The surprising arrival of a new fire truck brings both joy and chaos to members of Firehouse 51. Boden and Severide are asked to make peace with an old foe for the greater good. Brett receives family news while Foster plans a party with friends.

A series of mysterious gas leaks has members of Firehouse 51 puzzled and spread thin. Brett’s conflicted when her birth mother gets serious about tracking her down. Severide misunderstands his role as Cruz’s best man. Mouch bites off more than he can chew.

A series of teen opioid overdoses sees Severide partner with Sean Roman, but begins to suspect there’s more to the story than his old friend is telling him. Casey tries to be there for Brett as she considers her birth mother’s offer to meet.

The crossover continues on Chicago P.D. S07E15 Burden of Truth (II).

Boden is on edge after starting a new fad diet. Casey and Severide disagree on a call. Brett’s birth mother shares life-altering news. A familiar face has a proposition for Herrmann.

Things get personal for Casey and Gallo in the aftermath of a suburban house fire involving a mother and her young son. Herrmann campaigns for more respect. Kidd has an idea for giving back to her community.

Lt. Severide teams up with Seager and the OFI when a motel structure fire turns suspicious. Firehouse 51 members become amateur sleuths following a Reddit post involving one of their own. Brett continues to get invested in her birth mother, Julie.

Tension builds when a group of rabble-rousers attempt to lock down the firehouse. Brett is faced with a monumental decision. Cruz readies himself for a big day. Gallo and Ritter attempt to launch Firehouse 51 into the social media age.

When one of 51's own gets injured on a call, Lt. Severide becomes obsessed with helping out. Foster contemplates a big decision. Kidd is concerned for one of her high school trainees.

Firehouse 51 welcomes a new member to the team, whose presence could provide some complications. Brett's leadership shines during a scary call. Boden sees great potential in Kidd and proposes an idea that could have lasting repercussions.

Brett and Mackey find their lives in peril. Casey and Brett tread in unfamiliar territory. Severide chases a memory while Kidd adeptly solves a firehouse problem. Ritter puts himself in harms way during a harrowing call.

A mishap on the aerial ladder in the midst of a fire rescue leaves Mouch shaken and questioning his abilities. Kidd looks for support from Severide while Casey and Brett discuss their future.

While completing a task assigned by headquarters, Boden makes an unforeseen connection. Gallo is forced to make a surprise rescue to one of their own when the firehouse is called to the site of a construction explosion. Mouch reignites an old feud.

When Firehouse 51 is called to the scene of a dangerous blaze inside a 10-story storage unit, Herrmann and Cruz find themselves trapped inside a freight elevator with all communications cut off.

Gallo makes a split-second decision during a dangerous fire rescue leaving Casey steaming that his direct orders were not obeyed. Kidd feels a strain in her relationship with Severide. Brett and Mackey find themselves searching for answers following a series of suspicious calls.

A fire at a homeless encampment leaves Severide and Casey searching for answers. Cruz is shaken up after a close call. Ritter lends a helping hand to a victim.

A call to a familiar location brings back mixed emotions for Severide. Herrmann heads out for a vacation. Casey is not thrilled with his replacement.

Mouch, Gallo, Ritter and Mackey report for training. A nasty blow to the head brings Casey unimaginable pain.

A series of suspicious fires sends 51 on a search for the cause. Casey continues down a troubling path. Mouch is looking to make his long-awaited dream come true.

A new recruit with ties to the CFD tests Serveride's patience. Violet receives a mysterious note that sends her and Brett on a hunt for the person who wrote it.

While Mouch makes an incredible save, all eyes are on a mystery man who helped save his neighbor. Casey worries about his future at the CFD.

A mysterious caller who is in danger relies on Kidd to help save her and her brother. The firehouse helps Cruz get ready for fatherhood.

A fire breaks out at a pet food factory and Casey and Severide help the owner, Pete, get to the bottom of it. The annual garage sale takes place at 51 and everyone is on edge.

Severide and Casey try to find the best fit for Kidd. Ritter, Gallo and Violet help plan an event for Mouch.

The firehouse reacts to some exciting news, a mysterious stranger arrives and a shocking call takes Severide's breath away.

Firehouse 51 deals with the aftermath of the capsized boat rescue. Gallo, Ritter and Violet discuss plans for a side gig.

A video of Casey from the roof rescue goes viral. Mouch sets up a Little Free Library at Firehouse 51. Herrmann breaks protocol.

Griffin learns the truth about his father’s death and reveals why he really came to visit Casey. Gallo, Ritter and Violet take steps to expand their microbrewery business.

Kidd spreads her wings as a lieutenant. Chief Hawkins rides with Ambulance 61 to learn more about Brett. Casey takes a trip out of town. A Ritter date night turns into an emergency situation.

Casey makes a life-altering decision. Gallo, Ritter and Violet agree to an interview and photo shoot. Brett and Mouch launch the paramedicine program. Cruz comes closer to fatherhood.

A major security breach in the city’s computer networks forces Firehouse 51’s senior leaders to take matters into their own hands. Severide gears up for an arson investigation.

Gallo clashes with the new lieutenant temporarily filling in for Casey. Severide closes in on a dangerous and deadly arsonist.

Severide and Herrmann clash over office space. Boden looks at Pelham’s past as he considers making him permanent. Gallo’s resentment of Pelham comes to a head. Brett and Ritter force Violet to confront her true feelings for Gallo.

Gallo, Violet and Ritter debut their microbrewery business at Winterfest. Brett prepares to present her paramedicine program to an oversight panel. Firehouse 51 gets in the holiday spirit.

Stella Kidd returns to Firehouse 51. The team must work together to put out a potassium fire in a tunnel. After that incident, Ritter begins to worry about a young cop who witnessed the fiery death of a truck driver.

On a call with Station 37, a firefighter is struck by a power line and decides to lash out after her injury. Brett is visited by Scott and Amelia. Violet gets a surprise envelope. The rest of 51 enters a contest.

Boden, Kidd and Severide work together to protect one of their own. At the Fire Academy, Herrmann meets an inspiring young man. Talk of the annual CFD Gala dominates the firehouse.

Severide and Seager team up to investigate a fire at the home of a troubled young woman. Pelham moves into 51's rumored cursed office. Kylie assists Kidd with Girls on Fire.

Chief Hawkins goes above and beyond to help Brett and Violet with a problem. Kidd pursues an open lieutenant position. A blast from the past asks Mouch and Herrmann for a favor.

Following an injury in the aftermath of an industrial fire, Severide and Seager work together to investigate an anonymous tip. Kidd searches for the right person to fill the opening on Truck 81.

Cruz forms a bond with a young immigrant boy he meets while fighting an apartment fire. Squad makes plans to prank the newest member of their team.

Severide and Kidd work with CPD regarding a suspicious car wreck. Hawkins and Violet's relationship is in jeopardy. Chloe and Cruz adjust to a new family dynamic.

Firehouse 51 must band together when one of their own is taken hostage.

Firehouse 51 tackles a fire caused by a dropped jet engine, and one of their own is accused of a theft related to the incident. Kidd and Boden disapprove of Kylie's potential new love interest.

A family friend asks Herrmann for some advice on opening a bar. Tensions run high between Emma and Violet. Kidd struggles to keep her team together.

Mouch and Ritter work together to solve a murder mystery. Severide and Cruz tackle a food truck fire. Gallo goes to see Hawkins about Violet.

The big wedding day arrives and Firehouse 51 welcomes Casey back to celebrate the joyous occasion. Emma's plans to replace Violet come to a shocking end.

Kidd and Severide's honeymoon is interrupted by a dangerous person from their past. Kidd's former academy classmate joins Firehouse 51. Brett and Violet reflect on their relationships.

Javi spends a couple of shifts at Firehouse 51. Kidd and Carver work together to help Carver's former boss. As Hawkins and Violet's relationship blossoms, Gallo turns his attention elsewhere.

Kidd recruits Carver, Capp and Tony to help prepare her new lieutenant's quarters. Severide and Det. Pryma pair up to work a police investigation. Firehouse 51 fights a movie theater fire.

Kidd gets a glimpse into Carver's chaotic personal life. Mouch and Herrmann receive an unexpected gift.

Firehouse 51 hosts a Halloween open house. Kidd and Severide help a young girl after she gets kicked out of her home.

Severide and Kidd investigate an explosion at a jewelry store. Cruz and Chloe take steps to make Javi a permanent part of their family. Gallo, Ritter and Mouch try to bond with Carver.

Herrmann is tasked with fulfilling a man's dying wish. Kidd reflects on her Girls on Fire program after one of her students graduates from the Fire Academy. A heckler harasses Firehouse 51.

Det. Pryma asks for Severide's help on a case involving explosives. Gallo and Carver clash after Gallo improvises on a call. Violet encourages Brett to start dating again.

Severide struggles with the cost of helping Det. Pryma with the Martucci case. Gallo campaigns for Herrmann to represent 51 at the National Firefighter’s Association’s Winter Conference. A familiar face makes a shocking return.

Det. Pryma's case comes to an explosive end with Kidd and Carver's lives in danger. Brett installs an infant safe surrender box at 51. Violet is determined to take Emma down.

Firehouse 51 prepares for their semi-annual firehouse inspection. Brett fights to save her paramedicine program. Commander Martin Pearce asks Severide for a favor.

Truck and Squad clash after a tense call rescuing a doomsday prepper. Herrmann struggles with Cindy's diagnosis. Violet gives Brett and Gallo dating advice.

Firehouse 51 helps Herrmann put on a school fundraiser. Carver's troubled brother comes to town. A grateful citizen is determined to thank Brett and Severide for saving his life.

An annoying floater takes a romantic interest in Violet. Ritter catches a local politician in a compromising position. Mouch and Severide help Trudy with an arson investigation.

Kidd, Seager and Carver investigate a fire at the city stables. Kylie clashes with some of the firefighters over changes due to budget cuts. Herrmann struggles to keep it together as Cindy's condition worsens.

Cruz feels the burden of his increased responsibilities. Kidd, Gallo and Carver get caught in the middle of a gang war on a call. Herrmann wrangles Trudy for help lifting Cindy's mood.

Mouch builds a classic firetruck model for the Deputy District Chief but needs some assistance from Gallo and Ritter. Brett and Violet encounter multiple victims with a strange set of symptoms. Cindy's chemotherapy results loom over the Herrmann family.

A familiar face returns to Firehouse 51 to serve with Kidd on a special task force. Mouch and Capp work to keep Tony safe, as he's days away from breaking the CFD's perfect attendance record. Old grudges resurface when Gallo reunites with a family member.

Boden, Ritter, Herrmann and Kidd work together to take down a local politician responsible for a chemical fire. After his aunt's accident, Gallo worries about their future.

Herrmann works on becoming a better man after Cindy's cancer journey. Kidd bonds with a homeless victim on a call. Kylie takes her firefighter exams. A harrowing call takes a toll on Brett.

Carver deals with the fallout of his arrest. Brett searches for closure with the baby she rescued. Capp weasels his way into the Firehouse 51 group chat.

Brett waits for life-changing news. Herrmann encounters a psychic with a grave warning on a call. Kidd finds a new lead on the Homeland Security case.

Firehouse 51 is forced to share space with Firehouse 17. Kidd and Herrmann fight over Ritter. An arson case tests Kidd and Severide's relationship. Firehouse 51 says goodbye to one of its own.

Mouch sets out to change his legacy and nickname. Ritter pushes Herrmann to see a doctor. Brett searches for the perfect wedding venue.

After witnessing a domestic dispute, Brett and Violet decide to take the investigation into their own hands. Mouch vets Truck 81's new firefighter. Herrmann relies on something new to aid him on the job.

Julia spends a couple of days at 51. Boden's stepson returns, desperate for Boden to help his mother. After a little girl starts a fire in her backyard, Kidd and her team decide to dig deeper.

After their defibrillator malfunctions on a call, Brett and Violet search for answers. Herrmann tries to find the perfect home for his new recliner. A secret from Gibson's past comes to light.

Firehouse 51 welcomes back some familiar faces and says goodbye to Brett. Violet scrambles to decorate Brett's wedding venue. A call at the expo center takes a shocking turn.

Violet clashes with her new partner. Severide discovers a hidden stash of money on a call and squares off against the cops working the case. Mouch gets a parking ticket.

A hazmat call at a dialysis center leads to a shocking discovery. Boden clashes with Paramedic Chief Robinson. Carver notices a concerning change in Gibson's behavior.

Severide, Kidd and Van Meter investigate a fire at a recording studio. Kylie helps James keep a secret from Boden. Mouch struggles to maintain boundaries with a paramedicine client.

Severide steps in as ranking officer at 51. Kidd fights to save her Girls on Fire program. Cruz's family is threatened when someone from Javi's past resurfaces.

Severide goes for an unexpected ride on Truck 81. Ritter's worlds collide when his secret cop boyfriend helps 51 track down Severide and the missing rig.

Severide and Violet risk clashing with Paramedic Chief Robinson after Lennox makes a dangerous decision on a call. Capp and Tony attempt to break a world record. Cruz and Chloe's marriage problems come to a head.

Boden makes a decision that impacts the race for Deputy Commissioner. A tense call brings up painful memories for Carver and Damon. Mouch struggles to adjust to the new Truck.