Marine Tommy Hill returns home to his adoptive family, the McCormicks, who have organised a homecoming party for him. He enters the house, looks stunned at the unexpected reception, then collapses on the floor and dies of a stab wound.
Arriving at the scene, McGee and Ziva follow a trail of Hill's blood, which leads them to a mobile phone that is just about to be swallowed by a street cleaner. McGee goes through the machine's collected dirt and detritus and eventually comes out with the phone, which Abby determines must have belonged to the killer.
Abby looks through Hill's laptop and discovers a couple of interesting things. In the past three days Hill had devoted a lot of energy into trying to hack his way into the Virginia State website, but without success. GPS records show that the laptop stayed within a very limited range, apart from once when it was taken to a location in the middle of nowhere. McGee and DiNozzo head there and uncover a strongbox with $50,000 in it...
Ducky’s autopsy reveals that Hill was injected with a sedative and that the tip of the syringe broke off in the victim. Tests on the syringe and the phone produce a suspect called Curtis Beane. After his manager tries to cover for him, Curtis is found on the roof of the taco restaurant where he works. But the combination of Curtis’s fraught mental state and a heavy dose of heroin prove to be too much.
Abby is able to recover more from the mobile: some surveillance photographs, but they are not of Tommy Hill but his adopted sister, Lindsey. Investigations reveal that she is not everything she appears to be. Has she been fooling her adoptive parents? To what end? And what connection does she have with the owner of the taco business?
McGee's grandmother is implicated in the killing of a Navy lieutenant.