Callen and Sam resume their undercover identities as a prisoner and guard to infiltrate a white supremacist group believed to be in possession of stolen nuclear material, while Kensi transforms herself into a tattooed biker to play the part of Callen's girlfriend. Also, Callen's first meeting with Hetty is revealed.

The team searches for a former Marine and expert sniper who escaped a veterans hospital when they discover his connection to the leader of an extremist group. Also, the case reminds Kensi of her past as a sniper.