Rule Fifty-One is the twenty-fourth and final episode in NCIS Season 7 and the 162nd episode of the entire NCIS series.
After being captured by a member of the Reynosa Cartel in the previous episode, Gibbs meets the head of the Reynosa Cartel and realizes that his past, one he kept concealed from his NCIS colleagues for twenty years has returned with a vengeance with everyone he cares about being placed in great danger while Ziva, having passed her citizenship tests finally becomes an official citizen of the United States of America.
A while later, a bag is removed from Gibbs's heads with Gibbs blinking to adjust to the light.
Dean then throws the bag aside and quickly produces a knife which he then uses to cut the plastic rope binding Gibbs's hands together.
As Dean walks away, a young Mexican woman thanks him.
Gibbs quickly snaps out of his confusion and glances over at the woman who asks him if he knows who she is.
As this goes on, another guard and Dean are both standing a few meters next to each other, both acting as bodyguards and armed with weapons.
Gibbs remarks that the woman in question is Paloma Reynosa, the head of the Reynosa Cartel while Paloma then walks past Gibbs, holding two glasses while also giving Gibbs a small, disgusted look.
As Paloma places a glass on the table, Gibbs, not one to back down reveals that Paloma is the head of the Reynosa Cartel while down in the gardens, a woman is busy training a white stallion horse.
As she turns, heading over to stand opposite him, Paloma wants to know what else Gibbs knows.
As Gibbs remarks that the drug trade is recession proof, it cuts to the garden where the unknown woman is continuing to train while revealing that the group is in a big mansion with gunmen loyal to the Cartel posted everywhere.
Glancing out, Paloma remarks that Tennesse Williams once said that "We are all sentenced to solidarity confinement inside our own skins for life".
As Dean looks on, amused, Gibbs simply rubs his hair, brushing some dust off.
Paloma then remarks that surrounded by men with guns, she thinks of this often and as Gibbs finishes, Paloma states that it's beautiful, sad but frank.
Looking Gibbs straight in the eye, Paloma wants to know Gibbs considers himself a frank man.
Still seated, Gibbs just looks at Paloma.
Paloma then remarks that Williams also said that "all cruel people consider themselves as paragons of frankness" before stating in a tone laced with anger and bitterness that she would expect nothing less from the man who murdered her father.
Gibbs continues silently glancing at Paloma.
Paloma then takes a sip of her scotch while glancing at Gibbs.
Gibbs's right hand is now wrapped around his glass of scotch.
Paloma finishes sipping and remarks that she sees that Gibbs chooses his words carefully because that's good.
Gibbs just looks away.
Paloma then reveals that Gibbs's life depends on them.
It then cuts to Gibbs who reveals that he doesn't usually drink scotch before he drains his glass in one move as Dean silently looks on.
In the morgue, with Jason Paul Dean's body now on a slab, Ducky asks Vance for his opinion.
Vance states that Dean killed Macy, killed Bell and played some part in the shootout between the cartel members and Bell's men before suggesting his belief that Dean might have killed Franks too.
- It's revealed that Ziva has passed her official citizenship exams.
- Ziva later takes part in a ceremony and subsequently becomes a citizen of the United States of America, presumably severing her ties with Israel in the process.
- As a result of his interaction with the Reynosa Cartel, Gibbs later creates a new rule- Rule 51 which is revealed to be "Sometimes you're wrong".
|Leroy Jethro Gibbs||Mark Harmon||Special Agent in charge of the NCIS Major Case Response Team.|
|Anthony DiNozzo||Michael Weatherly||Senior Agent and second-in-command of the NCIS Major Case Response Team.|
|Ziva David||Cote de Pablo||NCIS Probationary Agent and also a member of the NCIS Major Case Response Team.|
|Timothy McGee||Sean Murray (actor)||Junior Special Agent of the NCIS Major Case Response Team.|
|Abigail Sciuto||Pauley Perrette||Chief Forensic Specialist of the NCIS Major Case Response Team.|
|Leon Vance||Rocky Carroll||Director of NCIS.|
|Donald Mallard||David McCallum||Chief Medical Examiner of the NCIS Major Case Response Team.|
|James Palmer||Brian Dietzen||Assistant Medical Examiner.|
|Margaret Allison Hart||Rena Sofer||Attorney.|
|Alejandro Rivera||Marco Sanchez||Mexican Justice Department official and Paloma Reynosa's younger brother.|
|Jason Paul Dean||Dylan Bruno||Ex Army Ranger now working as a mercenary for Paloma Reynosa. Later dies in a gunfight between himself, his men and Tony, McGee and Ziva.|
|Paloma Reynosa||Jacqueline Obradors||Head of the Reynosa cartel and Alejandro Rivera's sister.|
|Michael Franks||Muse Watson||Former NIS Agent who is also Gibbs's mentor.|
|Jackson Gibbs||Ralph Waite||Gibbs's father.|
|Shannon Gibbs||Darby Stanchfield||Gibbs's deceased first wife.|
|Federale 1||Ariel Llinas||A Mexican Police Officer who appears in the episode.|