Contains spoilers for Season 6, Episode 3, “Resurrection”.

Sid Baker’s return could be good news for River Cartwright, especially after so many losses. But Slow Horses gives its characters little time to enjoy a reunion. In “Resurrection”, the third episode of Season 6, questions about the years of silence are interrupted by a pursuit that forces the two to work together before establishing whether they can still trust each other. Meanwhile, Jackson Lamb tries to understand who is eliminating people connected to Slough House, and Diana Taverner seems to recognize the problem more quickly than she is willing to admit.

River has reasons to want answers from Sid. He believed she had died, and now he must reconcile the relief of finding her alive with everything he does not know about her absence. Their conversation mixes explanations, resentment and the familiarity that Jack Lowden and Olivia Cooke recover so easily. There is chemistry between them, but it does not automatically resolve the mistrust. River wants to believe Sid; that does not yet mean he knows enough about her.

Jim and Jane put an end to the possibility of a quiet conversation. Sid says the assassins are after her, and the escape becomes a succession of attempts to lose them. The couple keep catching up with the two, giving the reunion an urgency that leaves every explanation incomplete. Sid knows the threat comes from Russia and knows aspects of that operation, but she does not understand why she has become a target. It is an important distinction: she has information River does not possess, without necessarily having an explanation for everything that is happening.

For the audience, Jane speaking Russian with Jim reinforces that connection. We also see Jim preparing a poison while Jane goes after Sid and River. The detail deserves attention, but the episode does not yet give us grounds to predict its use, unless you read it here. The threat works precisely because of the combination of the assassins’ persistence and the variety of means at their disposal. Escaping one encounter is not enough to get beyond their reach.

In London, Standish and Shirley seek out Louisa, who tries to pretend she does not know them. Her reaction has its humour, but it does not last long: leaving Slough House does not seem enough to leave its problems behind. Louisa ends up joining the two, and the group goes after Moira. Their decision comes in time to prevent another death, as they find her in danger of dying from gas poisoning.

The rescue brings together four women with very different personalities, without turning the emergency into an interlude of harmony. Moira remains irritating even after being saved, preserving one of the series’ qualities: danger does not suddenly make anyone more pleasant. Louisa, Standish and Shirley have to deal with her while organizing their own survival. The four buy a gun and head towards a safe house, because figuring out what is happening is no longer enough; they need to prepare for the next attack.

Lamb, accompanied by Roddy, seeks out Reece Nesmith, who escaped the scene of his father’s murder. Reece tries to flee again but cannot avoid the encounter. The two want him to confirm that he saw Frank Harkness kill his father. The investigation therefore depends on a witness who has obvious reasons to be frightened and whose information could help Lamb connect the deaths to Frank’s presence.

Diana faces pressure of a different kind. After appearing on the television programme, she returns to work and receives a reprimand from her superior. Irritated, she tries to preserve her authority and composure, but her reaction to Emma Flyte exposes how defensive she has become. Emma senses that something is wrong and tries to understand the situation; Diana resists her approach and ends up threatening to send her to Slough House.

The threat is especially revealing in an episode in which the slow horses are trying to prevent their colleagues from being killed. For Diana, Slough House still serves as an instrument of punishment, a place to dispatch anyone who bothers her. Her need to control the conversation outweighs her willingness to listen to someone who has noticed her difficulty. The scene leaves Emma facing a boss who demands obedience at precisely the moment she needs cooperation.

Lamb visits her at home and asks the question she does not want to answer: has Diana angered someone enough to provoke retaliation involving hiring Frank? Her reaction suggests that the hypothesis immediately makes sense to her, although she still does not know who is behind it. Even so, she does not share what she has understood. She tries to keep Lamb at a distance and throws him out, as though ending the visit were enough to end the problem.

It is a difference the episode explores well. Lamb seeks information to protect his team; Diana manages what she can reveal and what she prefers to conceal. She seems to understand more than she admits, but that does not put her in control of the situation. The more she insists on maintaining her air of authority, the more apparent the fragility of her position becomes.

Sid and River find shelter at a widow’s house, where their reunion gets some room to breathe. Their closeness continues to work, although it does not eliminate the unanswered questions. Jim and Jane arrive there too, forcing them to flee once more. Sid and River create a distraction by destroying their pursuers’ car and make it to the road, where Coe appears to rescue them. He had gone looking for River.

Coe’s presence adds a very particular discomfort to the escape. He admits that he enjoys killing people and asks whether that makes him a sociopath. River carefully replies that he believes it does. The humour comes from the calmness of the conversation, but its substance remains disturbing. Coe can save a colleague and, shortly afterwards, reveal a relationship with violence that makes his help less reassuring.

He also asks River whether he really trusts Sid. The affirmative answer comes without much conviction, preserving the doubt that has accompanied the two since their reunion. When Sid insists that she needs to warn Diana, without clearly explaining why, that trust becomes even harder to assess. They stop at a petrol station to look for a telephone, and River accompanies Sid.

The episode ends when Jim and Jane arrive at the same location, spot the two and follow them, armed. “Resurrection” brings Sid back to River and Louisa back to the group, but those returns restore no sense of safety. Instead, they bring together people who must quickly decide whom to believe, with incomplete information and assassins drawing ever closer. Lamb continues trying to assemble the bigger picture; Diana continues withholding pieces. For those in the line of fire, that difference could prove very costly.