While playing on a frozen pond, two brothers discover a dead Marine underneath the ice, prompting the main NCIS team to be called in to investigate. While processing the scene, the team also discover the bodies of three dead gang members who are later identified as being part of a dangerous street gang, La Vida Mala or LVM for short. The team soon discover that it could be connected to the fact that the gang accidentally killed another Marine a year previously while they attempt to find out who was responsible for the Marine and the gang-bangers's deaths.