"Loch Henry" is the second episode of the sixth series of the anthology series Black Mirror. It was written by the series creator Charlie Brooker and directed by Sam Miller. Alongside the rest of the sixth series, it premiered on Netflix on 15 June 2023. The episode follows Davis (Samuel Blenkin) and Pia (Myha'la Herrold) as they make a true crime documentary in Davis's run-down hometown in Scotland.

Brooker reflected on the cinematic style of true crime documentaries and how he and his wife had considered traveling to Scotland after seeing its depiction in a documentary. "Loch Henry" was the first episode set in Scotland, as the setting of "Crocodile" was changed to Iceland; 18 locations in Scotland were used for filming. The episode criticises the effects of true crime media on victims and highlights dissonant attitudes of the creators and consumers of true crime media. The episode references other Black Mirror events through newspapers and other text; its themes were compared to "Joan Is Awful", which is also about streaming television.

The episode placed around the middle of critics' lists of Black Mirror installments by quality, though most reviews aggregated by Rotten Tomatoes were positive. Reviewers wrote negatively of the episode's moral but positively about the characters and acting. Critics were ambivalent towards the plot twist.

Davis McCardle (Samuel Blenkin) visits his childhood home in Loch Henry, Scotland, with his American girlfriend Pia Koreshi (Myha'la Herrold). They met in a film course and are pursuing Davis's idea for a documentary about an amateur conservationist in Rùm who prevents illegal egg collecting. Davis's mother Janet (Monica Dolan) cooks for them, but she and Pia are uneasy around each other.

Davis introduces Pia to his friend Stuart King (Daniel Portman), who runs the only remaining pub in Loch Henry, the Lochside Inn. Stuart's father Richard (John Hannah) is an alcoholic. The former tourist haven is run down because, in the 1990s, resident Iain Adair (Tom Crowhurst) made national headlines as a serial killer. Davis's policeman father Kenneth (Gregor Firth) was called to Adair's home after Adair made drunken comments about missing tourists. Adair shot his parents, Kenneth and himself. Wounded in the shoulder, Kenneth acquired MRSA in hospital and died when Davis was eight.

Pia proposes a true crime documentary about Adair. Davis is worried about its local impact, but Stuart believes the film will bring in tourism, and Janet is happy to voice her anger about Adair's responsibility for Kenneth's death. They pitch it to the producer Kate Cezar (Ellie White), who wants new information uncovered. Davis, Pia and Stuart break into Adair's abandoned home and find evidence of torture in the basement. They film footage with an old camera, taping over Janet's Bergerac VHS cassettes. Returning home, they get in a car accident. Davis has to stay overnight in hospital, where Richard—recovering from a fall down the stairs—voices opposition to the documentary.

Pia discovers that Janet's cassettes contain recordings of Janet and Kenneth alongside Adair, torturing his victims. Pia flees the house, unable to get phone service. Janet realises what Pia has discovered and pursues her. Pia hits her head while fleeing through a stream in darkness and dies. Janet returns to the house, leaves a note next to evidence of her crimes, and hangs herself.

Davis assists on a Streamberry documentary about his parents' criminal activity. An interview shows that Richard suspected Janet and Kenneth's involvement after unnerving sexual activity with the couple. Kenneth killed the Adair family and wounded himself so it appeared that Iain worked alone.