WARNING: MAJOR SPOILERS ahead for Black Bag.

Those who see Black Bag in theaters may want to bring a pen and paper to make sense of its serpentine ending. Marketed as an action thriller, Black Bag is more of a psychological puzzle of cloaks and daggers – or should I say steak knives – that requires viewers’ full focus to piece together. Given its swift 93-minute runtime, Black Bag requires much more of your attention than your time, packing in a flurry of dialogue-driven exposition and twists that can make one’s head spin by its end. Those who dig to keep up, however, are rewarded by its relentlessly sharp pace.

Black Bag is Steven Soderbergh and David Koepp’s latest collaboration and second feature film of 2025 following their psychological horror Presence. The film is a sleek and Sєxually charged cat-and-mouse game full of professional liars, some better than others. Michael Fᴀssbender, who has a recent knack for playing robotic agents and killers with flat affects (The Agency, The Killer), leads the ensemble cast of Black Bag alongside the alluring and cold-as-ice Cate Blanchett. Their George and Kathryn are a married couple working for London’s National Cyber Security Centre, whose dangerous cyber weapon “Severus” has been leaked into Russian hands.

Who Leaked Severus & Betrayed The National Cyber Security Centre

The Leak Came All The Way From The Top

The Severus leak came from the top of the National Cyber Security Centre – Pierce Brosnan’s Arthur Stieglitz. Arthur enlisted the help of Col. James Stokes, the second in command to George Woodhouse, to leak Severus into Russian hands with the intention of inspiring some controlled chaos. Severus is an advanced and top-secret cyber weapon that has the unique ability to melt down any nuclear reactor core. It was the most prized possession of the NCSC, which makes it quite astonishing that Arthur would want to put it in enemy hands. Ultimately, Arthur and Stokes are the key villains and traitors behind the leak.

James Stokes’ Deception & Ideological Motivations Explained

Stokes Believed In Sacrificing Some For The Greater Good

Like the other mole suspects given to George by another high-ranking NCSC official, Philip Meachum, James Stokes is a highly intelligent and sophisticated liar. He differs from the rest in his ideological beliefs, as exemplified by the question George asks him during his polygraph test towards the end of the film. George questions whether it is morally acceptable to kill some for the greater good, which is exactly what Stokes believes. He wanted to leak Severus as bait for the Russians to start a world war, justifying the extreme intervention of the Western military forces, thus “ending” the war (presumably in Ukraine).

Margaret Langford & The $7 Million Bank Account Explained

Stokes Lied To George To Place Heat On Kathryn

Stokes deceives George by intentionally raising his suspicions against Kathryn. He tells him that Kathryn used an antiquated alias “Margaret Langford” to open a bank account in Myanmar with $7 million deposited in a lump sum. This led George to suspect that Kathryn sold Severus to the Russians – Andrei Kulikov, who she met on the bench in Zurich, and Vadim Pavlichuk, a Russian general on house arrest who escaped as George redirected satellite surveillance on Kathryn. Stokes later reveals that he was incorrect about Kathryn being the only one to use the alias, which is why George nearly kills him on the fishing boat.

How Pierce Brosnan’s Arthur Was Involved In The Severus Leak

He Enlisted The Ideological Stokes To Do His Dirty Work

Arthur is the shadowy spearhead of the Severus leak who set up the “plan” and “counter-plan” to make George and Kathryn suspicious of each other. Arthur is also likely responsible for killing Meachum even though it was Stokes who actually poisoned him. All the resulting actions of Stokes, Zoe, Freddie, and Clarissa were ripples of the skipping stone that Arthur cast. Arthur did not want George to find out that Stokes leaked Severus on his orders, so he deployed a defensive plan that would manipulate George into believing Kathryn was the mole. Arthur severely underestimated the bond and trust between George and Kathryn.

George’s “Plan” & Kathryn’s “Counter-Plan” Explained

Arthur Wanted George & Kathryn At Odds To Avoid Detection

Arthur’s initial plan was to make George suspicious of Kathryn, which he did successfully by having a movie stub for “Dark Windows” planted in their bedroom trash can. When George asked Kathryn if she wanted to see the film, she acted like she had never seen it before (which she genuinely hadn’t). George suspected that she secretly met with someone in the theater and was being dishonest about her schedule. This led George to snoop on her calendar, discover the coordinates for the Zurich meetup, and redirect the satellite so that Pavlichuk could escape and George would be convinced that Kathryn was the mole.

The counter-plan was to have Freddie tell Kathryn that George was spying on her in Zurich, which would raise her suspicions of him. This is exactly what he did the night she returned from Switzerland. It was all designed to have George and Kathryn turn on each other, which was the only way that Arthur and Stokes could get away with the Severus leak.

What The Russians Were Going To Do With Severus

Pavlichuk & Kulikov Were Seemingly Hired By Arthur & Stokes

Arthur and Stokes wanted two Russian criminals – Pavlichuk and Kulikov – to use Severus to initiate meltdowns of one or more nuclear reactor cores outside Moscow. This would have greatly exposed Russian citizens to radiation, who are apparently the “10,000 to 20,000” innocent people whose lives were at stake if Severus was deployed. It appears that Pavlichuk and Kulikov were planning to strike a terrorist attack against his own country using Severus, which could have “ended the war”, presumably between Russia and Ukraine. The $7 million under Margaret Langford might have been Pavlichuk and Kulikov’s payment – if Kathryn hadn’t tipped off the CIA, who bombed their car.

Why George Didn’t Kill Freddie, Zoe & Clarissa

They Were Pawns In Arthur & Stokes’ Scheme

Once Stokes admitted to betraying George, setting up Kathryn, and leaking Severus at the second dinner party at the Woodhouse residence, he panicked and tried to kill George. While intelligent, Stokes actually believed that Kathryn put a loaded gun on the table, which ended up being a fatal mistake. George captured Stokes’ confession on a hidden camera and began negotiating the terms of his surrender. Once he fires two blanks at George, Kathryn pulls out an actually loaded gun and shoots Stokes ᴅᴇᴀᴅ.

Freddie, Zoe, and Clarissa were involved in Arthur’s elaborate scheme but to varying and lesser degrees. Zoe only knew about Severus because Stokes, her ex-boyfriend, rambled about it one night in private while he was drunk. Zoe told Freddie, who she was secretly having an affair with for the last 2 months, about Severus. Freddie’s affection for Zoe led him to ask his actual girlfriend, the newbie Clarissa, to plant the movie ticket stub in George and Kathryn’s bedroom wastebasket. Since they were all pawns in Arthur and Stokes’ plot, George spared their lives.

The Real Meaning of Black Bag’s Ending

Trust No One – Except Your Spouse

Black Bag is a whirlwind of plot twists and revealed deceptions that rest on a simple concept: trust no one (except your spouse). While Soderbergh and Koepp arguably should have allowed a few breaths in their rapid-fire film, the tension they establish and hold is gripping and makes for a fascinating “he said, she said,” until the human lie detector George sets the record straight. Similar to murder mysteries like Knives Out, Black Bag keeps you guessing about the guilty party up until its final moments and thoroughly entertains with a fantastic ensemble cast.

Black Bag revels in a near-paranoid mindset that questions everything and everyone, which would sound unhinged if it weren’t for its setting. The film is inherently about deception and how even the best liars will eventually find it hard to keep track of their tricks. There are intriguing philosophical elements that are important to the story but blown through rather quickly given its incredibly lean runtime. Black Bag may be worth watching twice to gain a complete grasp on the entirety of its plot. If anything, it proves that the sancтιтy of marriage still applies in even the ᴅᴇᴀᴅliest of circles.