In Mazatlan, Mexico, Mike, Bud's brother, becomes involved in a barroom fight with a local, who later dies. Harm and Bud, with help from Bud Sr., eventually discover the cause. Mac successfully defends a Marine bulldog in a paternity suit.

Representative Latham and another ride an MV-22 Osprey aircraft; just above the sea a minor mishap occurs. Latham holds an inquiry, and Harm and Mac take part. Harriet investigates an old case of innocence. The guys start planning a party.