Abby is...
TONY: Trying to match them from the Mercedes from the chop shop. CHOP SHOP - NIGHT
TONY: First severed head? GIBBS: And? GIBBS: There may have been a mix-up. GIBBS: They had a human head in the trunk of a car, McGee. I will handle the Captain's remains with the utmost respect, Ma'am. Look. Serpent and the Rainbow? Since the Captain died of natural causes, it's going to take the judge a while to sign off on it. TONY: Shelves lined with body parts is not bad? That's a promise. The ashes are bogus. ZIVA: Found who, Abby? who performed the autopsy on our Captain four months ago.
Plan: A: Navy sailors; Q: What group of people were operating an illegal automotive chop shop? A: Ziva; Q: Who finds a severed head in the trunk of a stolen car? A: Abby; Q: Who matches the head to a Navy Captain who died four months earlier? A: Things; Q: What goes from bad to worse when Abby discovers that the ashes that the Captain's wife and young daughter have been looking after since his death are bogus? A: the hunt; Q: What does the team go on to find the missing body parts? Summary: While arresting a group of Navy sailors who were operating an illegal automotive chop shop , Ziva finds a severed head in the trunk of a recently stolen car. Abby later matches the head to a Navy Captain who died four months previously. Things go from bad to worse when Abby discovers that the ashes that the Captain's wife and young daughter have been looking after since the Captain's death are bogus, sending the team on the hunt for a possible "human chop shop" operating illegally and the Captain's remaining body parts.