Athena and Buck are in a race against time to rescue the rest of the 118 following the fire in the bio lab.

Following the tragic events at the lab, the 118 must come together to lay their fallen hero to rest. Meanwhile, despite her own grief, Athena re-investigates the death of a child to help a grieving mother.

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.

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

What goes around comes around for an unremorseful widower, an arrogant fitness club owner and an unsuspecting thief. Meanwhile, Bobby gets a surprising phone call from his doctor after donating at Chimney's blood drive, and Athena confronts Michael after having a heart-to-heart with their kids.

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 members of the 118 race to rescue a man who claims he was carjacked, shot and buried alive. Then, they arrive at a home where the owner thinks her roommate is a ghost, Hen receives a visit from the past, and Athena and family are concerned that Harry is still haunted by visions of Jeffrey.

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.

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.

It takes a team of people to help answer the famous question, "911, what's your emergency?" Detective Athena Grant works as a member of the police force, handling cases that require her sharp mind and expertise, while also trying to juggle her own family drama. Bobby Nash and his team of firefighters help execute the daring rescues that often come along with these life-threatening situations. Meanwhile, Abby Clark spends her days taking and fielding emergency calls at the 911 call center, but constantly desires to know what happens after she sends help.

The 118 races to rescue a little girl in a runaway hot air balloon and help with a city power outage caused by a hijacked tree-trimmer truck; Athena's investigation into a serial rapist case puts her life in jeopardy.

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.

Athena, Bobby and the 118 "speed" to the rescue to save a family whose pick-up truck has been rigged with a pipe bomb which will detonate if the vehicle slows under 55 miles an hour. Meanwhile, Eddie has a rough transition into his new job, Buck makes an impulsive relationship decision and Hen is reluctant to accept her new partner in Chimney's absence.

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.

A full moon keeps the crew busy with some of the craziest calls yet, as Athena investigates a potential home invasion and "faces off" against a rabid criminal. Meanwhile, Abby helps investigate the murder of a caller, Bobby and Buck have their hands full at a yoga studio for pregnant women and Hen's past may become her future.

A man over-exerts himself exercising; a groundskeeper is cut by his chainsaw. An explosion occurs at a retirement community. May gets an emergency call from a suicidal teen.

The 118 are called to the tarmac when a flight attendant reaches her limit with her flight's passengers. Athena discovers that quarantine has pushed a couple to their breaking point. Meanwhile, Eddie worries Christopher will not accept him dating, Buck reconnects with an old flame and finds himself in the middle of Albert's new relationship and Maddie and Chimney make a big decision about their baby.

The Santa Ana winds bring in a variety of weirder-than-usual emergencies as the 118 respond to a family dog retrieving a severed hand and a young woman sleep-driving into the station. Bobby worries about his AA sponsor. Denny questions Hen and Karen about his biological parents. Chimney thinks he's found the perfect house for him and Maddie.

Upon her return to shore, Athena's son, Harry, finds himself in trouble with the law. Meanwhile, Buck grows envious as Eddie forms a close bond with someone else, and the 118 rescue a woman who's stuck on receiving a rose at an iconic mansion.

Following the devastating fire at the Nash home, Bobby's fate remains uncertain, while Athena embarks on a mission to uncover the truth. Meanwhile, Hen and Karen engage in a heated custody battle, while Christopher grapples with forgiving Eddie.

The 118, still reeling from their recent loss, is dispatched to a mass casualty event after a high-rise apartment building collapses. Then, Athena and Chimney have to work together to save a familiar face.

Bobby and the 118 race to the rescue when an abandoned oil well erupts and causes a massive sinkhole in downtown LA. Athena investigates a 30-year-old cold case involving a casino robbery. Buck fears his relationship with Taylor might be ending, and Hen meets a man from her mother, Toni's, past.

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

Hen and Karen welcome a new addition to their family, while a call unfolds involving a person’s limb that’s taken on a mind of its own. Meanwhile, Eddie and Marisol take a closer look at their relationship, and Buck navigates his new feelings.

Maddie and Athena investigate a case surrounding an abducted mother and child as Hen and Karen learn more about Mara’s family history. Meanwhile, Eddie grapples with unresolved feelings for someone from his past.