Doors, corridors and shelves become the battleground in “Cleaning Up”. River and Louisa are trapped inside the archive with Donovan, while Lamb reaches Catherine just as another attack closes in. Tearney and Taverner can discuss the consequences over a drink; their subordinates have to survive them. The episode makes the relationship between an elegant office conversation and an ugly field order brutally direct.
- Released
- 20 December 2023
- Runtime
- 41 minutes
- Source novel
- Real Tigers
- Director
- Saul Metzstein
Explore further
Watch and read
Open the official programme page or explore the source novel.
Detailed plot
Reveal episode spoilers
Duffy deploys Chieftain’s armed men around the records facility, blocking the escape route as well as preparing to force the main entrance. Hobbs and Sturges are sent to the house where Catherine is being held. At the Park, Tearney confronts Taverner about the scheme to remove her. The missing file concerns Footprint, a device intended to penetrate encrypted computer systems. The operation failed, people were harmed, and Alison’s attempt to expose the truth led to her being killed. Taverner has used Donovan’s search for answers to threaten Tearney’s position.
Tearney insists that the attack will destroy the evidence and the people who could use it. Inside the archive, River watches the cameras being disabled and tries to establish his authority at the entrance. Douglas cannot remember the override code under pressure, so River shoots the keypad to delay the attackers. They answer with explosives. A door that should protect official records now provides only a brief pause before the armed group breaks through. River retreats into the facility and tries to get help.
Lamb is occupied with his own rescue, so River contacts Marcus and Shirley. The two dismissed officers move towards the danger rather than leave their former colleagues to it. Marcus has weapons in his car, and they arm themselves for the approach. Douglas surrenders, hoping compliance will keep him alive. He is taken to Duffy and admits that he knows the affair is connected with Tearney. That knowledge seals his fate. Duffy shoots him, showing how little the operation’s targets have to do with whether somebody is fighting back.
River and Louisa barricade doors while Donovan continues looking for the document. The scale of the force sent against them makes Louisa take his suspicions seriously. Finding the file is no longer a private demand imposed on unwilling escorts; it could also explain why their own employer is trying to kill them. Outside, Marcus and Shirley discover the trap around the escape hatch, but Chieftain gunfire pins them down before they can simply clear a route. The rescue needs them to survive a separate fight first.
Lamb reaches the family house and pretends to be a beggar at the door. He knocks Sarah down and finds Catherine, who explains why she has been helping her captors. Before their departure can become straightforward, Hobbs and Sturges arrive. At the archive, Donovan finally locates the file. Ben takes a weapon from a fallen attacker but is shot in the neck. The discovery and the injury arrive together, denying the group any clean moment of victory. A grenade is thrown into the room and explodes, leaving River and the others amid smoke, scattered papers and unanswered questions about who can still get out.
Turning points
Reveal turning points
Douglas’s death is the point at which obedience loses its promised protection. He gives himself up, answers questions and attempts to cooperate with the people who claim official authority. None of that matters once he has said enough to become inconvenient. The sequence turns an abstract order to suppress witnesses into the killing of a person whose main responsibility was looking after records.
Louisa’s judgement of Donovan shifts through evidence rather than a persuasive speech alone. MI5’s response makes the possibility of a cover-up harder to ignore. She does not have to accept every choice he has made to recognise that something is badly wrong with the force being used against them. That distinction allows cooperation without treating the original abduction as harmless.
Marcus and Shirley’s return is also more than a reversal of Lamb’s dismissal. Their failings have been public and embarrassing, but the immediate question is whether they will abandon colleagues under attack. They do not. The episode lets an officer be compromised in one part of life and valuable in another, which is central to the appeal of Slough House as an ensemble.
The cross-cutting makes the distance between command and consequence feel indecent. Tearney and Taverner can measure careers and blame while River is measuring doors and ammunition. The same operation looks orderly from an office and terrifying from a corridor. By ending on an explosion inside a room full of records, the episode brings physical danger and the destruction of institutional memory into a single image.
Book vs show
Reveal book and television spoilers
Mick Herron’s Real Tigers (2016) centres its suppressed evidence on Project Waterproof and secret prisons. Television turns the damaging operation into Footprint, the failed surveillance technology discussed by Tearney and Taverner here.
The book calls the hired armed contractors Black Arrow. “Cleaning Up” gives the attack to Chieftain, continuing the renamed company’s role from the security test to the attempted cover-up.
Donovan’s emotional connection has also been redirected. The novel makes him Catherine’s former lover, while this episode frames his search around Alison and the relatives helping him. Catherine joins his cause through what she learns during captivity rather than a shared romantic past.
Characters and actors
River and Louisa must keep both the file and its seekers alive. Marcus and Shirley approach from outside, Lamb works at the house, and Catherine explains the case she has come to understand. Douglas is the civilian employee caught between archive procedure and an order to erase witnesses.
Linked locations
The underground archive supplies the main siege, with its records room, entrance and escape hatch defining the available routes. The Dunn family house becomes a second threatened refuge. Taverner’s office places the senior argument at a deliberate distance from both fights.
Trivia
Will Smith told TheWrap that Series 3’s threat comes from an internal MI5 struggle over a secret, rather than the outside antagonists of the first two series. The attack on the archive makes that distinction visible: the danger reaches the team through its own chain of command.
Questions and answers
Why is Douglas killed after surrendering?
Duffy decides that his knowledge makes him a witness to the cover-up. Cooperation does not protect him once he identifies the connection to Tearney.
Why do Marcus and Shirley return?
River calls for help. Despite being dismissed, they choose to go to the facility and try to save their colleagues.
Is the file found before the explosion?
Yes. Donovan locates it during the attack, but finding it does not create an escape route. The grenade leaves the group’s immediate survival unresolved.