With no memory of the night before, Lasalle's brother, Cade, turns to NCIS for help when he finds his girlfriend's body in the trunk of his car. Despite a mountain of evidence that implicates Cade, and the case being under Captain Jim Messier and Jefferson Parish jurisdiction, Lasalle is determined to prove his brother's innocence.

After receiving intelligence that the ports have been breached, placing the Navy and the Gulf Coast in harm's way, Pride and the NCIS team follow every angle to determine what has entered their city and how they can put a stop to the Broussard Syndicate, who seem to always be one step ahead of them.