A Naval Seaman and an infamous arms dealer are both found shot to death just across the Mexican border. NCIS:LA finds evidence at the scene that there was a wooden box the two men were trying to smuggle into the U.S. The Seaman's wife tells our team the box was filled with gold and her husband was hired to transport the box from the Sudan, through South America and into the U.S. The trail of evidence leads to the doorstep of a notorious Mexican drug cartel and when Sam and Callen confront the cartel members about the shooting a gunfight ensues. Callen and Sam get the drop on the cartel and a naive member gives them clues on where to find the shooter also revealing that heroin not gold was in the box. Our team tracks down the shooters location but find him dead after her snorted some of the boxes contents. Sam realizes it wasn't heroin in the box, but fine high-grade enriched uranium which will most certainly be used in a terrorist attack within days. Callen and the team rush to track down the terrorist who they now know plan to disperse the uranium in an air conditioning system at the L.A. Convention Center before they kill thousands.
