On a crowded Friday evening in London, counterintelligence officer George Woodhouse meets his boss, Philip Meacham, in a sober office. Meacham informs George that a high-priority computer program codenamed Severus has been leaked and that five members of their National Cyber Security Centre team are under suspicion. One of the five is George's wife, Kathryn St. Jean, who also works in the service. Meacham gives George exactly one week to discover which of the five is the mole and recover the trail of the breach.

George and Kathryn decide to bring the four other suspects into close proximity. They invite satellite imagery analyst Clarissa Dubose and her boyfriend Freddie Smalls, the agency psychiatrist Dr. Zoe Vaughan, and Colonel James "Jimmy" Stokes to dinner at their flat. George laces the food with a mild sedative to lower inhibitions and watches the group interact, ostensibly to ease tension but also to observe. He begins a game where each guest must propose a resolution for the person on their right, using the guise of party entertainment to pry. The game turns personal: when Clarissa names Freddie, she accuses him of sleeping with another woman. Freddie shrugs it off; Clarissa becomes enraged, grabs a steak knife and stabs him through the hand. Freddie, heavily impaired by the drugs, responds with indifference as blood trickles and the dinner spirals into awkward silence.

That same night, George combs his own home for clues. In Kathryn's bathroom waste basket he finds a ticket stub for a film called Dark Windows. When he confronts her, she tells him she has no idea about the ticket. Their private friction simmers while the official investigation intensifies. Meacham falls ill at his home later that evening, convulsing suddenly in front of his wife. He dies, and medical opinion records a heart attack, though the timing and those convulsions lead George to suspect poisoning. The death heightens urgency within the agency and piles pressure on George to act quickly before the mole vanishes.

Determined to access Kathryn's workspace, George sneaks Meacham's ID card into Kathryn's handbag so he can retrieve it from her desk. With the card he gains entrance to secure systems and discovers on Kathryn's computer a log that records an upcoming trip to Zurich. He also finds encrypted notations and movement patterns in staff accounts that hint at misdirected funds. A short time later, while George is fishing alone, Colonel Stokes approaches him and relays a startling discovery from agency records: someone used a false identity--"Margaret Langford"--to funnel seven million pounds into a Zurich bank account. Stokes's tone implies deeper collusion and he warns George that money and false paperwork suggest a planned exfiltration rather than a careless leak.

Kathryn attends a counseling session with Dr. Zoe Vaughan to discuss the strain her job puts on her marriage. Zoe asks whether Kathryn chooses career over her husband; Kathryn replies that her responsibilities are complex and that their superiors, particularly Arthur Stieglitz, view her marriage as a liability. In a separate encounter, Zoe and Stokes meet and end their romantic relationship. Stokes reminds Zoe that he has confided classified material about Severus to her and, with a quiet menace, implies she has limited options now that she knows sensitive information.

George pursues a surveillance angle. He asks Clarissa to discreetly re-task a spy satellite so he can monitor a planned meeting between Kathryn and a Russian contact in Switzerland. Clarissa hesitates but ultimately agrees. While Clarissa manipulates satellite feeds, George spies on Kathryn's rendezvous with a Russian dissident, Lieutenant-Colonel Andrei Kulikov, in Zurich. He believes the meeting may explain Kathryn's trip and possibly link her to the leak. During the brief window when Clarissa redirects the satellite, another Russian operative, General Vadim Pavlichuk, vanishes from a Liechtenstein safe house with a copy of Severus. This disappearance happens within minutes of the satellite realignment; Pavlichuk and the dissident Kulikov now carry the program as they head toward Eastern Europe.

Clarissa confesses to Freddie that she helped George with the satellite maneuver. The conversation brings Clarence and Freddie back to a fragile truce; Freddie, now aware of Clarissa's cooperation, goes to warn Kathryn that George suspects her of being the mole. That night, George and Kathryn speak frankly in bed. They compare what little evidence each has collected and conclude that someone is orchestrating events to make Kathryn appear culpable. They decide to work together to flush out the actual conspirator rather than let the agency pick them apart.

Kathryn uses Clarissa's technical access to track Pavlichuk and his companions. She hacks together location traces and funnels the coordinates to a CIA contact. The tracked convoy is intercepted by an allied drone as it travels through Poland; a precise strike detonates the vehicles and the operatives who carry the stolen Severus code are killed in the explosion. Kathryn watches the feed alongside George, and the pair record the last-known trajectories of the dissidents to reconstruct the leak's physical trail.

Back in London, George places Clarissa, Freddie, Stokes and Zoe under polygraph testing to determine when each of them first learned the existence of Severus. He excludes Kathryn, keeping her identity shielded while he evaluates the others' testimony and physiological reactions. The polygraphs reveal discrepancies and half-truths: Freddie and Zoe's answers suggest intimacy and knowledge of sensitive details; Stokes's responses show evasions that point to prior exposure. George collates the polygraph data, cross-references satellite logs, bank transfers and travel manifests, and forms a theory that implicates both institutional betrayal and personal entanglements.

Armed with his findings, George and Kathryn invite the four suspects back to their flat for a second dinner. This time, Kathryn places a pistol in the center of the table as the sole "prop" on a stark, white tablecloth. George tells the guests they will play a single-question game: each will answer one pointed inquiry meant to determine who betrayed Severus. The atmosphere is taut and methodical as George calls on each person with surgical precision. Under pressure, secrets unravel. George reveals that Zoe and Freddie had an affair and that Zoe learned of Severus through Freddie. He identifies two intersecting schemes: one orchestrated by Arthur Stieglitz and Colonel Stokes to leak Severus with the aim of triggering a nuclear meltdown and thereby destabilizing the Russian government to influence the conflict over Ukraine; the other devised by Zoe and Freddie to use Kathryn as a channel to stop that plan.

Stokes abruptly breaks the slow cadence of confession. He leans forward, voice flat, and admits that he conspired with Stieglitz to leak Severus as part of a scheme to precipitate the catastrophe. In his admission he confesses further to having murdered Philip Meacham, revealing that Meacham's death was not natural but deliberate. Stokes then lunges for the gun on the table, grabs it and points it at George. He fires twice. The first shots echo in the room, but they are not lethal--every cartridge in the weapon contains blanks. The air shudders with the sound, but no blood follows. As Stokes processes the failure of his attempt, Kathryn reacts instantly: she draws a second pistol from her bag and fires at Stokes, striking him. He collapses to the floor, bleeding from the wound. Kathryn stands over him with the smoking gun and delivers a stark admonition to the remaining staff: do not ever use their mutual trust as a tool against George and her again.

With Stokes dead on their living-room floor, George takes charge of removing the body. He loads Stokes into his car and later drives to a secluded lake. In the stillness of night he eases the body into the water and lets it sink, washing away the immediate physical evidence of the betrayal. The group conspires, under the threat Kathryn posed and the gravity of the admissions, to keep the incident contained rather than expose the full extent of the internal fracture; they choose to preserve the surface functioning of the service while burying the details of Meacham's murder and Stieglitz's role at higher levels.

George confronts Arthur Stieglitz by phone and then in person to inform him that the plot has failed. Kathryn demands that Stieglitz remove himself from his position, telling him that the severed chain of command and the loss of the operatives meant the larger destabilization effort has been undone. Stieglitz listens and, with the weight of exposure pressing on him, his calculations unravel. George and Kathryn insist their marriage and their loyalty to each other remain intact, and they take this moment to reaffirm their partnership in private. They sit together late into the night and go over the remaining loose ends.

One of the few loose ends is the Zurich account containing seven million pounds. The money remains in the misdirected account under the false name Margaret Langford, untouched and intact. At Kathryn's later interrogation she confirms that the account still holds the funds and that, despite the deaths and confessions, the cash was never spent by the conspirators. George reveals this detail to the agency in measured tones; the untouched account becomes a ledger entry in a broader file rather than the explanation of the leak itself.

The final scenes show George and Kathryn in their flat at night, side by side, physically and emotionally aligned after the tumult. They exchange quiet words that acknowledge both the violence that has occurred--Meacham's death, the drone strike in Poland, the killing of Stokes--and the precariousness of what remains: the money in Zurich, the highest levels of agency complicity represented by Stieglitz, and the compromised lives of the colleagues who must continue to work under the same roof. They close their curtains, light dimming to a soft hush, and hold each other, a couple who have survived public accusation, internal betrayal and lethal confrontation, while a file marked Severus remains active in a secure drawer and the Zurich account number awaits further action. The film ends with their quiet embrace and the unresolved ledger--seven million pounds listed but unspent--sitting as the last factual detail left in the open.

At the end of Black Bag (2025), the truth about the Severus leak is revealed during a tense second dinner party hosted by George and Kathryn. James confesses to conspiring with their boss Stieglitz to leak Severus and cause a nuclear meltdown, then shoots at George with blanks. Kathryn kills James with a real gun, and she and George reaffirm their loyalty to each other. The other suspects cover up James's death and return to work, while Kathryn warns their colleagues never to exploit their marriage again. The film closes with Kathryn's Zurich bank account still untouched, implying unresolved secrets remain.

The ending unfolds in a detailed sequence of scenes:

George and Kathryn, both British intelligence officers, invite the four other suspects--Clarissa, Freddie, James, and Zoe--to a second dinner party after George's investigation reveals multiple layers of deception. Instead of serving dinner, Kathryn places a gun on the table, signaling the gravity of the confrontation.

George begins by revealing secrets he has uncovered: Freddie and Zoe had an affair, and Zoe learned about the Severus program from James but tried to stop its dissemination due to her Catholic beliefs. George explains that there were two opposing plots: one by Stieglitz and James to leak Severus and trigger a nuclear meltdown, and another by Zoe and Freddie to use Kathryn to prevent this catastrophe.

Tensions escalate when James grabs the gun and confesses to conspiring with Stieglitz and killing their superior Meacham. He then fires twice at George, but the gun is loaded with blanks. At that moment, Kathryn draws her own gun from her bag and shoots James dead.

After the shooting, Kathryn firmly warns the remaining colleagues never to exploit the mutual fidelity between her and George again. The others dispose of James's body in a pond and return to their duties, maintaining the secrecy of the incident.

In the final moments, Kathryn contacts Stieglitz to inform him that his plot has failed and suggests he remove himself from the situation. She and George reaffirm their love and commitment to each other. The film closes with the revelation that the £7 million in Kathryn's Zurich bank account remains untouched, leaving an open question about her true loyalties and the unresolved mysteries surrounding the Severus leak.

Regarding the fates of the main characters involved at the end:

• James is killed by Kathryn after his confession and attempted shooting.
• Kathryn and George survive, reaffirm their relationship, and continue their work, though with a new understanding of the dangers around them.
• The other suspects--Clarissa, Freddie, and Zoe--remain alive and return to their roles, complicit in covering up James's death.
• Stieglitz's fate is left ambiguous, but Kathryn warns him off, implying his influence is diminished.

This ending scene-by-scene narrative highlights the complex web of loyalty, betrayal, and secrecy that defines the film's core conflict.

The movie Black Bag (2025) does not have a post-credit scene or any stinger after the credits. The credits run for about 4-5 minutes, but there is no additional footage or scene following them.

George's five major suspects for leaking the Severus program are satellite specialist Clarissa and her boyfriend Freddie, agency therapist Zoe and her agent boyfriend James, and reluctantly, his wife Kathryn.

George hosts two dinner parties where he uses truth serum and psychological games to expose secrets among the suspects. The first dinner devolves into chaos when Clarissa discovers Freddie's infidelity. The second dinner reveals multiple betrayals and plots, culminating in James confessing to conspiring to leak Severus and attempting to shoot George with blanks, after which Kathryn kills James.

Two plots are uncovered: one by Stieglitz and James to leak Severus and cause a nuclear meltdown, and another by Zoe and Freddie to use Kathryn to stop the leak.

George and Kathryn are both spies and married, which complicates the investigation as George reluctantly suspects Kathryn. Their mutual trust and love are tested but ultimately reaffirmed after the second dinner party and the resolution of the conspiracy.

Severus is a top-secret software program that, if leaked, could cause a nuclear meltdown and kill thousands. The investigation centers on finding who leaked Severus and stopping the resulting threat, with the program's leak being the catalyst for the film's espionage and intrigue.

The movie Black Bag (2025) is not family friendly; it is rated R due to language, some sexual references, and moderate violence.

Potentially objectionable or upsetting content for children or sensitive viewers includes:

• Language: Nearly 30 uses of strong profanity including the F-word and other harsh terms.
• Sexual content: A few implied sex scenes, partial nudity (e.g., a woman revealing a bra, sitting in a camisole), kissing scenes, and discussions of erotica and infidelity.
• Violence: Moderate violence including a man shot in the head with bloody detail, a stabbing to the hand (without blood), a car explosion causing two deaths, and a body burning alive.
• Themes: Deception, betrayal, infidelity, hostility, and moral ambiguity are central, with tense confrontations and threats.
• Other: Some drug use is implied (ecstasy mentioned), alcohol consumption, and a scene involving poisoning.

Overall, the film contains mature themes and scenes that are likely inappropriate for children and may be upsetting for sensitive viewers.