With the serial bomber still on the loose, numerous calls are coming into 911. 

The responders are called to an elementary school when a mysterious backpack is left behind but it turns out to be a false alarm. 

Eddie's family comes to town for Shannon's funeral and they tell him that he should move back to Texas. 

The team responds to a man whose hair gets caught in the engine of his vehicle, and a beauty influencer who breaks her clavicle while on social media after a worm comes out of her face. 

A package with a bomb inside is delivered to Athena's address, but is intercepted in time. After linking all the victims together, it's revealed that the bomber is the son of the man Bobby put away three years ago for arson. 

A bomb explodes on one of the 118 fire trucks, pinning Buck underneath. The son, Freddie, is strapped with a bomb next to the truck and he demands to see Bobby. Bobby confronts him and when he gets distracted, Bobby is able to disarm him. 

Buck has surgery and a titanium rod is placed in his leg. 

Bobby returns to the station, and Eddie gets off his probation period and becomes a member of the Los Angeles fire department. 

Athena and Bobby get married at the courthouse with her children present.