The story arc that started in the episode "Lockup" is concluded as Sam is sent on an undercover mission to Yemen. But the stakes are raised when it's revealed that the terrorist group have taken a young seven year old boy hostage and things get even worse for the team when it's discovered Nate's cover has been compromised which means that Sam has been exposed as well, forcing Callen, Sam and Nate into a fight for survival against terrorists who want them dead.
