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.

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 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.

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

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.

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.

Buck jumps back into the dating scene but fears he will return to his old ways; a woman goes to great extremes on a freeway overpass to get the attention of her husband; a couple have a car accident on their wedding day.

The holidays are naughty and nice for the first responders, who must deal with a stampede at a toy store, a mistletoe stunt gone awry and neighbors competing in a Christmas-light showdown. Meanwhile, Bobby contemplates his future with Athena, Chimney and Buck attempt to lift Maddie's spirits and Eddie must decide if he wants to give his son what he really wants for Christmas - a visit with his mom.

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.

Bobby Nash decides to move to Los Angeles in the hopes of restarting his life after a devastating tragedy that struck his family back in Minnesota, but in Los Angeles, he first meets Athena Grant and works his way to captain of the 118.

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.

Hen relives her evolution into the firefighter she is today as she recalls the first times she met Chimney and Athena.

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.

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

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.

Maddie goes for a ride-along with Athena in the hopes of being on the other end of a 9-1-1 call; Hen attempts to learn how to prevent her family from falling apart at the seams; disaster strikes at a military funeral and movie theater.

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.

When Metro LA's 9-1-1 system is hit with a massive system-wide power outage, the call center must go old school in responding to emergencies. The first responders must deal with explosions in multiple homes and a difficult child birth. Meanwhile, Michael confronts Bobby about parenting his kids.

A going-away party for a bank manager turns into an emergency, and then a mystery, as the first responders are accused of pulling off a daring heist.

The first responders deal with a calamity at a chocolate factory; a mail bomb explosion; Eddie receives some surprising news from Shannon; Maddie contemplates her future in the call center.