After an unexpected guest from the future, Nora West-Allen, appears at their home, Barry and Iris must figure out how to get her back to the future without disrupting the timeline…even more than she already has. Team Flash must work together to send Nora back, while simultaneously fighting off another villainous meta.

As Barry helps his daughter, Nora, become a better speedster, he and Team Flash also track down a meta stealing high-tech weapons, only to cross paths with a new foe named Cicada, who is hunting the very same meta with nefarious intent.

After Cicada's attack on The Flash, the team realizes they need to think outside the box to stop this dangerous new foe. Desperate to help her parents, Nora comes up with a plan that ultimately puts a member of Team Flash in danger. Meanwhile, Caitlin delves into her past.

Barry and Iris face the ultimate parenting test when Team Flash battles Spin, a savvy millennial armed with meta tech, and a dangerous agenda for their daughter, Nora. Ralph is feeling defeated until an unlikely source issues a challenge to help boost his confidence.

Nora lets something slip about the future that devastates Iris. In an attempt to distract his wife, Barry asks Iris to team up to stop a new meta, Rag Doll. Meanwhile, Caitlin learns something about her father.

Caitlin, Barry and Cisco learn something new about Caitlin’s father. Meanwhile, Iris and Sherloque follow a clue about Cicada.

While Nora grapples with unresolved anger over her father’s disappearance in the future, Barry and Team Flash must stop a powerful new meta, Weather Witch, from killing her own father, Weather Wizard.

Barry and Team Flash come up with a plan to stop Cicada. However, the plan calls for Barry and Nora to travel back in time to gather some key necessities. However, Barry hesitates, concerned about his daughter seeing certain parts of his life. Meanwhile, Sherloque takes his concerns about Nora to Iris, and Caitlin turns up a key asset in the fight against Cicada.

When Barry Allen and Oliver Queen wake up one morning and realize they have swapped bodies with each other, the two set off to find out what disturbed the timeline to cause such a shift. However, things quickly go from bad to worse when they present their case to Team Flash and the gang doesn’t believe them. Barry and Oliver realize they need Supergirl’s help and travel to Smallville on Earth-38 where they end up meeting Kara’s cousin, Clark Kent, and intrepid reporter, Lois Lane.

The crossover continues on Arrow S07E09 Elseworlds (II) and Supergirl S04E09 Elseworlds (III).

While Nora grapples with the revelation that Thawne killed her grandmother, Team Flash must stop the formidable team-up of a newly sprung from jail Weather Witch and Silver Ghost, a new meta-tech villain who can control engines and motorized technology. Meanwhile, Caitlin and Cisco discuss creating a meta-human cure.

During a battle with Cicada, Nora is severely injured. Due to Cicada's dampening powers, Nora's speed healing isn't working, leaving Barry and Iris scared for their daughter's future. Upset about his injured child, The Flash is filled with rage and confronts Cicada in a brutal battle. Meanwhile, Killer Frost keeps interfering with Caitlin's work on the cure.

When Sherloque wants to use a memory machine on Barry and Nora to help gain access to Grace's memories, Nora panics, fearing her parents will find out the secrets she's been keeping from them. Nora secretly decides to use the machine on her own which ends in disaster after she gets trapped inside Grace's mind. Barry and Iris go in after their daughter and Iris is brokenhearted by what she finds. Meanwhile, Ralph tricks Cisco into going out for a night out on the town.

Barry and Ralph must go undercover as criminals in an illegal black market to purchase a device that could help them stop Cicada. Once inside, Barry and Ralph find their morality tested as they slip deeper into the criminal world, eventually having to choose between committing a crime, or losing the means to defeat one of their greatest foes. Meanwhile, Iris investigates a lead on Cicada's whereabouts and ends up in a dangerous situation.

After Iris lands in serious danger, Nora races to save her mother. Barry puts the finishing touches on the metahuman cure, leaving Cisco with a rare night off so he decides to take Kamilla on a date.

When Gorilla Grodd attacks Central City, Barry and Team Flash find themselves teaming up with an unexpected ally to defeat – King Shark. However, when they hit a snag, they bring in Dr. Tanya Lamden to try to reach the man behind the shark, Shay Lamden.

With the meta-human cure ready to use, Barry and Team Flash must figure out a way to subdue Cicada long enough to take it. Killer Frost steps in to help with the plan. Meanwhile, Joe eases back into work, and Nora isn’t happy about the way her dad plans to stop Cicada.

Team Flash finds out that a suburban mom named Vickie Bolen is in danger and they race to save her. Upon meeting her, they discover she’s a meta-human who is hiding her abilities from her family. Barry encourages Vickie to share her secret with her family, which makes Nora realize she needs to come clean with her parents about Thawne.

After discovering that Nora is working with Thawne, Barry and Iris disagree about how to handle their daughter in the wake of this shocking news. Team Flash isn't sure they can trust Nora, so they go through her journal to find out exactly how she came to work alongside their greatest nemesis.

When Icicle returns to enact the next phase of his devious plan, Caitlin and her mother, Dr. Carla Tannhauser, must resolve their long-combative relationship to defeat the icy monster. After Barry makes a big decision about their family without consulting her, Iris decides to take matters into her own hands.

Barry continues to struggle with how he feels about Nora's betrayal. Brie Larvan, Joss Jackam and Peter Merkel return to Central City. Meanwhile, Cisco makes a bold decision.

Team Flash is on high alert after Cicada II threatens to unleash a dangerous virus that would put all meta-humans at risk.

Barry faces off with his oldest, and most formidable nemesis, Reverse Flash.

While Barry and Iris deal with the heartbreaking loss of their daughter, Nora, the team faces their greatest threat yet — one that threatens to destroy all of Central City. Meanwhile, Killer Frost has a brush with death that results in an unexpected new dynamic that will change her relationship with Caitlin forever.

Faced with the news of his impending death, Barry's resiliency suffers as he struggles to fight fate. Meanwhile, Cecile's career as a D.A. conflicts with her identity when she crosses paths with a villainous meta-human.

Knowing that Crisis is only weeks away, Barry prepares a member of Team Flash for life without him while hunting a terrifying meta-human with an unquenchable thirst. Meanwhile, Ralph uncovers a family secret.

Barry's efforts to prepare Cisco for Crisis are derailed when Cisco schemes to save Barry's life instead. Meanwhile, Ramsey Rosso uses his deadly new abilities to save his own life, while sacrificing his humanity in the process.

Cisco's faith in his ability to fill Barry's shoes as Team Leader is upended when he learns of a shocking murder. Meanwhile, Killer Frost trusts no one except herself to hunt down the dangerous Ramsey Rosso.

Barry turns his attention to prepping Elongated Man for life after Crisis and without The Flash, but Ralph ultimately teaches Barry a lesson. Meanwhile, Cecile faces her own moment of self-discovery while helping a recuperated Chester P. Runk reclaim his identity.

As Barry Allen stands on the threshold of his impending death in Crisis, his convictions are tested when the monstrous Dr. Ramsey Rosso infects The Flash with a mysterious, hallucinogenic contagion. Meanwhile, reporter Iris West-Allen uncovers a vast conspiracy.

With The Flash freshly infected by the monstrous Bloodwork, Iris and Cisco battle to help Barry take control of himself before he’s lost forever to Ramsey’s influence. Meanwhile, the rest of Team Flash fight to reclaim control of Central City from Bloodwork’s growing army.

Pariah enlists Black Lightning to help stop the Anti-Monitor after Flash-90 shares what he learned from his battle in ‘Elseworlds.’ With the help of Black Lightning, Barry, Cisco and Killer Frost come up with a plan that could save them all. Meanwhile, Iris has a heart-to-heart with Ryan Choi, while Oliver and Diggle return to an old familiar stomping ground.

The crossover starts on Supergirl S05E09 and Batwoman S01E09. It continues on Arrow S08E08 and Legends of Tomorrow S05E01.

After "The Citizen" prints an explosive story, Iris' life is threatened; refusing to hide from her attackers, Iris sets out to expose a dangerous organization; Barry must face the consequences of the Crisis and fulfill Oliver Queen's wish for him.

Barry and Iris plan a romantic dinner for Valentine's Day but their evening is interrupted by an old foe - Amunet; Frost gets into the holiday spirit and attempts to help Allegra reconnect with an old love.

After months of searching for Sue Dearbon, Ralph gets a lead on her whereabouts and finally comes face to face with his missing client. However, Sue refuses to return home to her family, and instead, takes Ralph on a daring adventure. Iris faces a new challenge while Barry considers a potentially dangerous request from a trusted source.

Feeling overwhelmed with all the changes since Crisis, Barry conducts an experiment that goes awry and puts him directly in Gorilla Grodd’s path. Expecting the worst, Barry is surprised when Grodd asks for his help. Unfortunately for both The Flash and Grodd, things get worse when another villain appears – Solovar. Meanwhile, Iris works with Eva to escape the Mirrorverse.

Kid Flash returns to Central City with a Zen attitude and new tricks up his sleeve. While thrilled to see his family again, Wally confides to Barry that he returned because he thinks there is something wrong with the speed force. Meanwhile, Cisco returns from his fact-finding mission across Earth-Prime.

The Flash takes on a dangerous new meta named Sunshine. Cisco sets out to help Nash.

After Black Hole hires Rag Doll to kill Joe, Singh suggests he go into Witness Protection but Joe refuses to stop investigating Carver. While investigating Carver with Cisco, Ralph runs into Sue. Iris becomes suspicious of Eva.

After recent events, Barry takes a closer look at his life with Iris. Eva makes a bold move.

When Godspeed returns, Barry turns to Hartley Rathaway for help. However, things get tense quickly after Barry realizes one of the changes from Crisis is that The Flash and Pied Piper are now enemies. Meanwhile, Iris tries to escape the Mirrorverse.

Barry considers a risky plan to save Iris from the Mirrorverse. Ralph attempts to stop Sue from making a grave mistake that could destroy her life.

When an experiment to save Barry's speed backfires, Nash Wells searches for a way to save The Flash and comes up with a dangerous plan. Meanwhile, Iris makes a startling realization inside the Mirrorverse and Cecile faces off with Rosa Dillon.

When Barry suddenly gains the power of speed thinking, he attempts to use his new gift to save Iris. While Barry is thrilled with his new power, Cisco is hesitant to trust it. Meanwhile, Eva must face a shattering truth.

As Eva becomes more powerful, Barry and team must find a way to stop her. They are shocked when an old friend - Sue Dearbon risks her life to help.

The Flash must deal with Abra Kadabra's sudden return to Central City. The villain is back with a vengeance and a score to settle. Meanwhile, Allegra deals with a tricky situation and Caitlin suspects something is off with Frost. Iris is forced to look at a dark moment in her past.

When a powerful new villain, Psych, channels and amplifies everyone's fears in order to wreak havoc on Central City, Barry realizes, with Cecile's help, that he must face his own worst fear in order to beat this new threat. Meanwhile, Joe is surprised when Kristen Kramer from the Governor's Municipal Logistics Commission drops into CCPD for a visit. Iris warns her father to dig deeper on why Kristen is actually there. Caitlin and Frost argue about how to live their lives.

Cisco and Chester travel back in time and get stuck in 1998, repeating the same day over and over again. The key to returning home is at Chester's childhood home but he refuses to visit.

When a mysterious ice powered enemy frames Frost for a brutal crime, she must find a way to clear her name; Barry and Iris have a surprise houseguest, and Joe continues to deal with Kristen Kramer.

With Frost facing an unjust punishment for her past crimes, Caitlin goes to great lengths to save her sister. Meanwhile, Barry's efforts to protect Speed Force Nora lead to a shocking discovery.

After a devastating betrayal, Barry turns to Timeless Wells for help. Meanwhile, Iris leads Team Citizen down a dangerous road in search of answers, and Cisco confides his biggest fear to Kamilla.

Iris is pushed to the limit as she seeks to uncover the mysterious truth about Psych; Barry initiates a new training system, that could potentially backfire, with devastating consequences; Joe and Cisco make life-altering decisions.

Barry and Iris come together to try and stop a dangerous force from destroying Central City.

Cisco and Kamilla tell the team they are leaving Central City. However, Barry, Iris and Caitlin don't have much time to digest the news because a new version of Rainbow Raider strikes and OG Team Flash must join together one final time to save the city.

Cecile is forced to confront her past in order to break free from a psychic prison. Meanwhile, Chester takes over for Cisco but makes a mistake that puts Barry in serious danger. Joe investigates Kristen Kramer's old military ties and discovers an unsettling truth.

When Ultraviolet returns to Central City, Allegra is determined to find her cousin and change her heart. Meanwhile, Joe finds evidence that Kristen Kramer may not be the good cop she appears to be.

When an army of Godspeeds attack Central City, Barry and Iris must put their family plans on hold and focus on the latest threat to their home. Meanwhile, Chillblaine is released from prison and claims to be reformed but Frost has her doubts.

John Diggle arrives in Central City with a weapon to help Barry stop the Godspeed War. Meanwhile, Allegra and Ultraviolet's new bond is put to the ultimate test, while Joe and Kristen Kramer are hunted by a former colleague of hers.

Barry and Iris greet their future children, XS and Bart, only for a shocking secret to threaten their new familial harmony. Meanwhile, the Godspeed war intensifies and threatens to destroy Central City.

The Flash enlists a host of speedster allies, including Iris and his children from the future - Bart and Nora West-Allen - to end the speedster war and defeat a deadly new adversary: the villainous Godspeed.

When a powerful alien threat arrives on Earth under mysterious circumstances, Barry, Iris and the rest of Team Flash are pushed to their limits in a desperate battle to save the world. But with time running out and the fate of humanity at stake, Flash and his companions will also need to enlist the help of some old friends if the forces of good are to prevail.

Despero warns The Flash that great tragedies will befall the speedster and cause him to lose his mind. Once that happens, Armageddon will begin. Determined to prove Despero wrong, Barry doubles down on proving his innocence but a devastating revelation from Iris pushes him to the edge and sends him to seek counsel from Black Lightning.

Barry meets Black Lightning at the Hall of Justice after things take a dire turn with Despero. Iris suspects something is off with Despero's vision of the future so she seeks help from a powerful ally.

Barry is shocked when Eobard Thawne returns in the most unexpected way, and with a tie to a loved one. Damien Darhk offers advice to Barry but there is a catch. An epic battle begins with Reverse Flash pitted against The Flash, Team Flash, Batwoman, Sentinel and Ryan Choi.

An opportunity presents itself for The Flash to end his lifelong battle with Reverse Flash for good, but the payoff could be too much for Barry and team to handle. Meanwhile, Mia Queen drops in from the future looking to save a lost loved one, and she won't let anything stand in her way.

After returning home from a visit for their parent's vow renewal, Bart and Nora quickly realize that things are not exactly as they left them. The duo race to repair any fissures in the timeline and restore everything back to the way it is supposed to be.

When a criminal invades the CCPD, Barry and Kramer must trust and rely on each other if they are going to make it out safely. Meanwhile, Caitlin learns a valuable lesson while out with Snow and Mark.

Barry trusts his instincts during a murder investigation, believing the suspect, despite the overwhelming evidence against him, meanwhile Iris gives Allegra an opportunity to be a mentor.

Barry and Team Flash get closer to figuring out the Fire Meta but no closer to finding him meanwhile Iris, needing a distraction, follows a story to Coast City.

Barry's desire to keep Team Flash safe is tested when Frost recklessly courts danger as she tries to stop the "Black Flame," meanwhile, Iris tries to help a teen girl reunite with her mother but unintentionally does more harm than good.

Barry and Chester may have found a way to stop the "Black Flame" from hurting anyone else meanwhile Caitlin decides to handle a situation on her own, possibly putting more innocent lives in danger.

With a new Meta terrorizing the city, Joe lends a hand to the local authorities, meanwhile Barry gets an assist from Cecille who helps to track the mass murderer.

Team Flash is under attack, and each must fight to save not only themselves but each other.

Team Flash uses the distraction of a bank robbing Meta to detract from the grief of losing someone they love.

The Flash gets an assist from XS. Meanwhile, CCPD enlists Chester for help when a mysterious device is found at a crime scene.

The Flash gets blasted with a shockwave forcing his body to age prematurely.

The Flash goes off the grid to look for answers about a new Meta in town. Meanwhile, Allegra pulls out all of the stops at CC Citizen Media, to protect a source and a friend.

With a new speedster in town, The Flash gets much more than he bargained for, meanwhile Cecile's powers experience a growth spurt allowing her to aid Team Flash on an entirely different level.

The Flash and team are in for the fight of their lives, meanwhile, Iris discovers the cause of her time sickness.

With The Flash still reeling from everything that just happened, the rest of the team rallies to support him when he needs it the most.

Barry creates a map book to guide him and Iris throughout their future in order to keep her safe, but the results are not what he expected, and instead, they relive the same day over and over again. Joe has a heart-to-heart with Cecile. A new big bad is introduced to Team Flash and friends and foes, old and new, begin to descend upon Central City.

Barry feels guilty for what happened to Caitlin, and Mark comes up with a plan that makes everyone skeptical. Meanwhile, Red Death looms in Central City and commands that failure is not an option. Joe asks Cecile to make a choice that leads Cecile to think about the greater good. Allegra and Chester take a step in a new direction. Lastly, old friends pay an unexpected visit to S.T.A.R. Labs.

Barry and Iris start to put together the pieces of what's happening in Central City and believe they know what the Rogues are after. Team Flash works together and recruits some unlikely allies to help, and the plan does not go as Team Flash expects. Meanwhile, Allegra does her best to avoid having a conversation with Chester.

The Flash is forced to make an impossible choice. With the power out in the city, Team Flash calls upon the Rogue Squad to help as Iris is visited by an old friend. Joe and Cecile work on finding a balance.

As the Red Death wreaks havoc on Central City, Barry and Iris come up with a plan and turn to Cecile for help. Barry is faced with what he thinks was his greatest mistake and the Red Death's greatest success. Khione wants to help Team Flash, but Barry can't risk losing her. Joe gives Barry a much-needed pep talk.

As Barry and Iris prepare for their new life, luck changes for those in Central City. Cecile takes on a case with Allegra's help, involving a string of unfortunate – and highly unexpected – events. Meanwhile, Chester and the team work with Khione to figure out her abilities.

Iris is visited by Nia Nal, as she needs Iris' help. When Iris and Nia fall into a fever dream and explore different possibilities for their lives, Barry, Chester, Allegra, and Cecile desperately try to help them. Meanwhile, Mark entertains Khione, but they have different ideas of what is fun, leaving Khione to feel that Mark is trying to make her something she is not.

A seemingly simple mold inspection at S.T.A.R. Labs leads to unexpected time anomalies. Barry and Iris try to make sense of the confusion - and figure out how to get back to their reality. Chester admits a secret to Allegra, which makes things awkward between the two, and Allegra relies on Cecile to act as a buffer. Meanwhile, Khione meets with an old friend of Team Flash.

Team Flash throws a surprise birthday party for Barry, but things go terribly awry when Ramsey Rosso crashes the festivities.

As Iris receives word of a career milestone, Barry is suddenly nowhere to be found. In trying to get back home, Barry runs across many familiar faces. Khione continues to figure out her powers, and Chester works on a suit for Allegra.

Iris is alarmed by Barry's disappearance and Cecile assures her everything will be ok, but does she know that for certain? Team Flash is affected by a mysterious substance and Khione develops a better understanding of what she can and cannot control.

Team Flash works together to figure out how to protect Barry, all while being very careful who they trust. Cecile is skeptical of the plan after an unsuccessful attempt. Khione's confidence in Chester enables him to convince Cecile to try one more time.

The Flash, the fastest man alive, is tasked with his greatest challenge yet, to save the timeline and save existence. Friends old and new gather for an epic battle to save Central City, one last time.