Threesome

David and Siri are a young Swedish couple living in London, comfortable and in love — until a night out with a stranger named Camille turns a flirtatious game into something neither of them can take back. Threesome is a slow-drip relationship drama built on one very bad decision.

The series is better than its premise suggests. It understands that the damage isn't the act itself but everything after it: the suspicion, the bargains, the way a secret reshapes every conversation. The Swedish production keeps things cool and understated, which suits the material.

Where it shines is in the couple's dynamic. David's guilt and Siri's stubborn curiosity pull in opposite directions, and the show lets neither off the hook. Camille, meanwhile, is written with enough ambiguity that you're never sure whether she's a catalyst or a predator.

It's not without flaws — a couple of subplots drift, and the pacing occasionally stalls — but as a character study of trust and its erosion, it keeps you leaning in.