A heatwave strikes LA and a groom leaves his wife at the altar, steals a car and the gets pulled over by Athena. While a tour bus full of passengers plungers into a building and a manhole blows off a workers arm.

A new firefighter starts at the station and garners a negative reaction from Buck, until the two work together to extract a live grenade from a man's leg. 

Buck's sister shows up at his house after escaping her abusive ex-husband. Later, Buck convinces her to stay in LA and gets her a job as a 9-1-1 operator. 

Bobby and Athena are dating but Athena does not want to take the relationship public due to fear. After an uplifting talk with her ex-husband, Athena decides she is ready to take things public.

The guys all vie for a firefighter calendar and Chimney is ultimately the one chosen after Hen submits a photo of him saving a girl.

An earthquake hits LA and Athena narrowly avoids serious harm when part of the freeway collapses.