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.

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.

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.

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.

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.

Bobby meets Athena's parents for the first time and Maddie attempts to end her marriage for good, causing Doug to insinuate himself even deeper into Chimney's life. Meanwhile, a tanker carrying a tiger shark crashes on the freeway and a gas leak in a plastic surgeon's office happens mid-surgery.

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.

When a murder weapon from a case close to Athena in the early '90s resurfaces, flashbacks to 1989 show how Athena joined the LAPD and became the police officer she is today.

Maddie fears for herself and her co-workers when the call center is taken hostage.

The 118 races to the rescue when the 9-1-1 Call Center goes up in flames. Then, Bobby risks his life to save a trapped May, and Claudette, Buck and Eddie work together to help an injured electrician, and Chimney and his brother team up as firefighters for the first time.

Another day in the life of the 118, as its members race to rescue a cliffside wellness retreat guru after his followers turn on him. Then, they respond to an emergency call at an upscale hair salon. Meanwhile, Maddie contemplates returning to work, Eddie and May make decisions on their future, as do Buck and Taylor, and the 118 gathers for a surprise wedding.