A massive tsunami hits the Santa Monica Pier, placing Buck and Christopher's lives in danger .

Athena, Maddie, Bobby and the 118 races to save lives after a massive tsunami hits the Santa Monica Pier and Buck fears the worst when Christopher goes missing.

The team races to save workers in a high-rise during a fire drill, car accident victims, and siblings fighting over a family heirloom. Buck gives Bobby surprising news. Eddie helps Christopher deal with the trauma caused by the tsunami.

The 118 races to help protesters at a slaughterhouse and a wife who finds herself trapped in a “rage room” with her husband’s mistress. Athena takes action after Michael, May and Harry experience a traumatic traffic stop.

Athena and the 118 respond to bizarre emergency calls on Halloween, including a flock of crows terrorizing a field trip, an office employee having a close encounter with an eight-limbed creature and a ghost-like girl wandering a neighborhood.

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.

Emergencies include a skating mishap at an ice show, an accident involving a self-driving car and a fulfillment warehouse robot going rogue. Meanwhile, Eddie's after-hours fight club gets out-of-control and Hen struggles in her relationship with Karen.

The 118 responds to debris from a meteor shower crashing into an apartment building and a deadly fire caused by a hazardous waste truck crash inside a tunnel. Meanwhile, Hen struggles with guilt over her ambulance accident, Bobby introduces Eddie to an old friend to help with his anger and Maddie receives an urgent call for help.

Holiday-themed incidents include a shopper pushed over the edge, a woman who is literally having a "Blue Christmas" and a luggage handler accident on a tarmac; Maddie revisits her past to embrace her future; Bobby receives shocking news.

The 118 responds to a skydiving trip gone wrong, a bank rep injured in a home repossession and a lovestruck assistant whose lunch run ends in disaster. Meanwhile, Athena and the family come to terms with Michael’s difficult health decision and Chimney’s half-brother from Korea unexpectedly shows up at his doorstep.

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.

Accidents happen at a bowling alley and a home renovation; Athena pursues a car thief.

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

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

The 118 fights an apartment building blaze; Athena's response to an accident call leads to a more sinister crime; Hen performs a risky medical procedure during a televised cooking show; Buck is inspired to reunite with his lost love.

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 118 rush to save lives in the aftermath of a massive train derailment.