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.

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.

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.

On one of the hottest days of the year, the first responders feel the pressure as harrowing incidents keep happening around the city, including a road rage accident involving a van full of tourists, an emergency at an auto-repair shop and a grenade. Meanwhile, Buck gets a surprise visit from his sister, and a handsome new hire Eddie jeopardizes Buck's chances of being chosen for a fireman calendar.

The first responders continue to deal with the fallout of a massive earthquake and its deadly aftershocks. Athena tries to keep the peace as Bobby and team continue to rescue victims from a collapsing high-rise hotel, both under the rubble and high above the ground. Maddie 's first day on the job involves helping a pregnant couple deliver their baby safely.

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.

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.

A series of ransomware threats leads to an overabundance of emergencies for the 118, including a medevac helicopter crash at a hospital and an air-traffic control tower system failure. Meanwhile Athena must revisit her traumatic attack when the case of the realtor serial rapist goes to trial, Eddie suffers a health scare and Maddie's postpartum depression worsens.

The 118 springs into action when a city-wide blackout and a record heatwave causes mayhem in Los Angeles. Meanwhile, Chimney confides in Hen about Maddie's condition, and Athena's worst nightmare comes true.

Athena and Bobby set off on their honeymoon cruise, but when duty calls, their vacation is put on hold. Meanwhile, a fighter jet traps a civilian, and an unusual incident leaves a couple stuck together.

After years of anticipation, Maddie and Chimney's long-awaited wedding day arrives. However, when the groom mysteriously vanishes, the 118 races against time to ensure he doesn't miss the most crucial day of his life.

After a victim of the apartment fire that changed Bobby’s life resurfaces, he searches to make amends. Driven by his need to right past wrongs, Bobby delves deep into memories of his childhood, unearthing moments from his fractured past.

Athena is tasked with safely delivering a prisoner to testify on a high-profile case. Meanwhile, a light plane is hit by a swarm of bees and sent careening into a passenger plane.

Athena's only chance of surviving and saving everyone on the flight is to attempt to land the plane before it crashes and call on the 118 for help.

The 118 responds to a fire at a local animal shelter and races to evacuate all the animals. Meanwhile, Maddie takes a 9-1-1 call that sets her on a quest for answers.

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.