While working on just a regular murder case with the rest of the NCIS team, Abby is almost killed by an evidence from the case and soon it becomes clear that the murder was staged, and that someone wants Abby dead. The team discovers some enemies from Abby's past, and they must find out who is the person, before the person kills Abby.

When evidence reveals an NCIS team member is a hitman’s latest target, the team must search through old case files to determine who is seeking vengeance.