‘Slow Horses’ Season 6 Episode 2 Recap & Ending Explained: Sid Baker’s Shocking Return Raises Even Bigger Questions

Apple TV’s premier spy thriller has built its reputation on turning genre conventions inside out, and the newest season has wasted no time proving that reputation is well earned. Season 6 dives into Mick Herron’s “Joe Country” and “Slough House” novels, reintroducing River Cartwright’s estranged father Frank Harkness right as former Slough House agents began turning up dead under increasingly suspicious circumstances.

That premiere ended with the killers setting their sights directly on River, leaving plenty of unresolved tension heading into the follow-up episode. “Daddy Issues” picks up that thread immediately, and by the time the credits roll, it has reshaped everything viewers thought they understood about the season’s central mystery.

The episode opens with Frank sitting in his car, watching a stray fox stare down a garbage van, before revealing exactly what he has been doing in London: stealing a file from Regent Park, MI5’s headquarters, with help from a low-level security operative named Andrew Nesmith. River, determined to track down his father, has Roddy Ho trace Frank’s rental car and then his phone, a search that eventually leads Lamb and River straight to Andrew’s home, where they discover him dead in what Frank staged to look like a suicide.

A CCTV camera near the scene reveals that a child was present at the time of Andrew’s death. Roddy identifies the boy as Andrew’s son, Reece, who has bounced between foster homes, and River quickly realizes the child may have witnessed something that makes him a dangerous loose end in Frank’s plan. That fear is confirmed when Frank references dealing with a “minor third-party complication,” a chilling reference to Reece himself.

Meanwhile, the assassin duo introduced in the premiere continues working through their list of former Slough House agents. After confirming that Kay White’s earlier death was no accident, the pair sets its sights on Moira Tregorian, posing as gas engineers investigating a leak before filling her house with gas and killing her in a way designed to look accidental.

Diana Taverner, already under scrutiny from the fallout of the premiere, finds herself facing even more pressure this week as the murders and the missing MI5 file start drawing unwanted attention from higher up. Lamb, meanwhile, heads to Regent Park to meet with Molly Doran, trying to understand why Slough House’s own records appear to have vanished from the Park’s official servers entirely, a gap that conveniently explains how the killers have managed to track their targets so easily.

By the episode’s midpoint, Lamb connects Frank directly to the theft of the stolen files, a discovery serious enough that he orders his own agents to go dark and stay off the grid until the threat can be contained. It’s a rare moment of genuine urgency from a boss usually more interested in insulting his team than protecting them.

Not everyone will make it out of Slough House alive.#SlowHorses Season 6 premieres September 16. pic.twitter.com/uznKQ0VSAE

— Apple TV (@AppleTV) August 18, 2026

The episode’s final stretch belongs entirely to River. After Roddy traces a taunting phone call back to the home of River’s recently deceased grandfather, David Cartwright, River rushes over expecting a confrontation with his father. Instead, he finds Sid Baker waiting for him inside, the former Slough House agent who was shot in the head and presumed dead all the way back in season one.

The episode ends right there, cutting to credits before offering a single word of explanation for how Sid survived or why she has resurfaced now, of all moments. It instantly reframes everything viewers thought they understood about Frank’s return and the murders piling up around him, setting up a back half of the season with a great deal left to untangle.

With Sid’s reappearance now tangled up with Frank’s scheme, Reece’s safety hanging in the balance, and Diana Taverner facing mounting pressure back at the Park, ‘Slow Horses’ has a lot of ground to cover in very little time.

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