A supposedly drunk woman at a bar kills a Brazilian diplomat and his bodyguards, then torches the bar. Deeks' mom's boyfriend Guy gets mugged, and Deeks leaves Kensi to cover for him while he goes to help Guy. The bodyguards were both ex-Marines. Harley and Kensi interview a survivor, Ellie, the bar owner, who said the woman threw her in the refrigerator before the fire. The thermite grenade used in the fire was from a robbery at a Marine base. Guy tells Deeks he was afraid someone would get ahold of his workout video with a client. Sam and Callen go to the home of one of the dead bodyguards, only to get fired upon. They and a SWAT team storm the house, which is a drug stash. Kensi and Harley find Jackson Horton, the suspect in the Marine-base theft, tied up. The assassin had picked up weapons at Horton's storage locker. Sam and Callen spot two gang members during a trip to the Brazilian embassy. The consul general tells Mosley that the dead man was plotting his assassination at the bar. Mosley convinces Souza to leave the country. The convoy is attacked by Pietra Ray, the daughter of an activist killed by the government. The convoy was a decoy, with Nell driving Souza in a delivery van. Kensi and Harley chase Pietra to a warehouse, but she escapes after an extended brawl with Kensi. Pietra tells Kensi that Souza was selling cocaine. Souza denies that. Pietra had planted a tracker on Kensi, and then calls Kensi on her phone, telling her to evacuate the building before she fires a missile into the Boatshed. Kensi goes after her, while the rest move Souza to the most reinforced part of the building. Souza pulls a gun on Mosley, but she escapes. Kensi talks Pietra into surrendering. Souza is sent home to face charges.