A night at an amusement park takes a deadly turn when a roller coaster malfunction leaves lives hanging in the balance. Abby reaches out to Buck; Athena and Hen respond to an unusual home invasion.

Bobby and his team respond to an emergency at a children's birthday party that leaves lives hanging in the balance. The crew jumps into action after one of their own is involved in a devastating accident. Athena tries to cope with a tragedy that hits way too close to home and Abby is confronted with a life-changing decision for her mother and makes a connection with Buck.

In the aftermath of a deadly plane crash, Bobby and team race to help the survivors, while Athena deals with panic and chaos at the airport. Bobby confronts his past demons; Athena is out for revenge against a group of teen bullies; and Abby delivers an important message from a 9-1-1 caller.

The crew races to an emergency when disaster strikes at an Indian wedding. Abby enlists the help of Buck to try and find her mother and, for the first time, meets Athena face-to-face. Meanwhile, Bobby has a difficult time confronting his past and Hen struggles to make the right decision.

On Valentine's Day, a surprise marriage proposal goes awry with dangerous consequences. Athena attempts to help a desperate woman and unintentionally joins the Lonely Hearts Club. Bobby and Chimney pull holiday duty and learn about the "Casanova Fracture" and Abby and Buck go on their first official date.

The first responders race to help a homeless man crushed in a garbage truck, a mother and son in a crashed elevator and extreme hoarders entombed in their house. Meanwhile, Athena jumps into to the dating pool, as Buck and Abby's relationship is tested by her ailing mother.

The first responders take calls to help an unusual domestic disturbance, a "death" at a psychic's and a horrific motorcycle crash. Meanwhile, Bobby dips his toe into the dating pool, Abby takes a walk down memory lane, Buck is confronted by his past actions and Athena tries to start her new life.

Athena contemplates accepting a promotion that will take her out of the field.

Halloween finds the first responders racing to the rescue at a cemetery, a haunted hayride and a spooky Hollywood parade; Meanwhile Maddie thinks she has received a "ghost" call from a missing hiker; Hen finds herself facing with a life or death situation with the father who abandoned her; Eddie reconnects with his estranged wife.

The 118 deals with a situation where a stunt driver is placed in a precarious position, two mail bombs are detonated and a teenaged social influencer loses their mind; Eddie's family decides to visit; Buck confronts a deadly series of events.

The 118 responds to a viral stunt gone haywire, a disaster at a couple’s fishing trip and an epic first date fail. Meanwhile, Athena investigates a woman who doesn’t remember being shot in the head and Eddie is forced to have a difficult conversation with Christopher.

Eddie's journey to rescue a boy from a well turns into a mission to save himself from his past.

In the aftermath of the dam break, massive mudslides wreak havoc throughout Los Angeles.

The members of the 118 make calls to save a bridezilla at a disastrous wedding and to a mother trapped on her balcony. Meanwhile, Hen plays medical detective when her mother, Toni, falls ill. Also, Eddie and Christopher receive a visit from Carla, Athena uncovers a secret Bobby has been hiding that puts their marriage on the rocks and Maddie struggles with adjusting to motherhood.

In the aftermath of the shooting, Athena and the 118 are on high alert when a sniper is targeting members of the LAFD. Meanwhile, Maddie makes a life decision. Season finale

The members of the 118 are called to series of emergencies around Christmas Eve. Then, Eddie struggles with an emotional Christopher.

The 118 race to the rescue at a renaissance faire, then an office building when an overbearing boss is poisoned. Athena fears for May's life when she encounters a disturbed young man. Buck babysits Jee-Yun as Maddie and Chimney begin house-hunting. Eddie and Carla prepare Christopher for his first school dance.

As Buck's life hangs in the balance, he dreams of a world where he never became a firefighter, for better and worse.