A man is found in the woods with a gunshot wound to his head.
Ducky and Gibbs are doing their thing, but are thrown for a loop when the team’s director, Vance, shows up on the crime scene.
He's there because he has seen these crime scene details before.
The director confirms that the murder must was committed by a female North Korean operative, Lee Wuan Kai, who he theorizes killed the doctor, using her signature style of two gunshots strategically positioned just so, after forcing him to treat her.
Vance tells the team to be on high alert – the two have a history and she is very deadly. In the former Yugoslavia in 1992, he put a slug in her chest, but she somehow survived, taking out his partner and leaving Vance shot as well.
He's determined to finish the job this time.
The team finds Kai left her DNA - one hair, placed just so - on the victim’s body for them to find. She's not being all that covert.
Vance is then stunned when Kai calls him at home and is sitting in a sports car right outside his driveway. What is her endgame?
The team later learns - a little too late - that Kai is in town to kill a North Korean official who has left that country's government. She puts two slugs in him and while surgery saves his life, poison embedded in the bullets finishes him off for good.
Vance and Gibbs talk to the North Korean government via back channels. They assure NCIS that Kai is not acting on any mission from them, and they wish her captured and prosecuted as well. Hmm.
Meanwhile, McGee has a new love interest, a really cute redhead, who he meets at the coffee shop. Things are going well ... a little too well. That's both from DiNozzo's standpoint (jealousy) and McGee's (safety).
When she shows up to visit him at work, McGee gets suspicious. He never told her he worked for NCIS. He questions her about this and she pulls a gun on him. She's an operative working for the North Korean government to kill ... Kai.
Just then, Kai shoots her dead, leaving McGee alive. What the ...
Gibbs puts together that the doctor they found earlier and the North Korean official she killed later both helped shape her early-childhood transformation into a killer. She's taking out the people responsible for ruining her life, and the North Koreans know it.
Thus McGee's "girlfriend" trying to take her out before the NCIS can get her to possibly defect or reveal what she knows.
Vance returns to his home to find Kai pointing a gun at his wife. Kai reveals that she is there because she wants Vance to kill him in order to finally end her pain.
It is up to him to finish the job, she says. Vance hesitates and tries to talk Kai down. He doesn't have to. His wife pulls a gun of her own and ices her for good.