The episode centers on a violent eruption at a popular food truck festival in Los Angeles.

A deadly cartel is desperate to recover a massive, lost shipment of drugs hidden inside produce—specifically avocados (hence the pun "Guacaine").

The cartel begins robbing and attacking food trucks that received the tainted produce.

The situation escalates at a grocery store where a young boy is taken hostage by a cartel member holding a live grenade. Luca devises a plan for Hondo to dispose of the grenade in a dumpster just as it detonates, successfully saving the child. Personal Storylines

Nichelle arrives at her community center to find it ransacked. Terrified by the lack of safety, she considers owning a gun for protection. However, after a practice session at the shooting range with Hondo, she realizes she cannot take a life and decides against it.

Deacon deals with his son, Matthew, getting into a fight at school after another student claimed all S.W.A.T. officers are killers. Deacon teaches Matthew that responding with violence is not the right way to defend one's family.