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.

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.

When a toddler falls down a pipe and becomes trapped, the 118 must rely on more than their skills to rescue him. Meanwhile, old wounds are opened when members of the 118 race to the aid of a man dealing with a divorce.