The film is explicit and not for general audiences:
Note: Despite the explicitness, the film is not pornographic. The sex scenes are deliberately mundane, repetitive, and emotionally cold — serving the theme of routine desire. Stranger.by.the.Lake.AKA.L.inconnu.du.Lac.2013....
The narrative follows Franck (Pierre Deladonchamps), a handsome, melancholic young man who spends his summer days at a secluded lake popular with gay men looking for anonymous sexual encounters. He spends his time cruising the woods, swimming, and striking up a friendship with Henri (Patrick d'Assumçao), an older, overweight man who sits on the beach claiming he comes only to "rest," observing the proceedings with a detached curiosity. The film is explicit and not for general audiences:
Franck’s routine shifts when he becomes infatuated with Michel (Christophe Paou), a charismatic and virile mustachioed man. One evening, Franck watches from the woods as Michel drowns his current lover in the lake. Instead of reporting the murder to the police, Franck is paralyzed by a mix of fear, moral confusion, and an intensifying sexual attraction to the killer. Note: Despite the explicitness, the film is not
Franck enters into a passionate affair with Michel, fully aware of what he is capable of. As a police inspector begins poking around the beach asking questions, and Henri grows suspicious of the new couple, the idyllic summer setting turns into a suffocating trap.
The film’s core exploration is the link between sexual desire (Eros) and death (Thanatos). Guiraudie presents a world where the pursuit of pleasure is inextricably linked with danger. The men who visit the lake seek the "little death" (orgasm), but the setting offers the possibility of actual death. Franck’s attraction to Michel is not despite the murder, but seemingly heightened by the danger it represents. The film posits that desire can be blinding, leading one to embrace their own potential destruction.