Chemsexeur is the story of a gay man who likes to party, to have fun, and who sometimes takes so-called "recreational" drugs and who, as the evenings go by, meets people and falls into chemsex until he forgets the rest.
Several notables from the Chamonix region are found murdered in their homes. To move forward with investigation, police captain Thomas Delhaye decides to release Juliette Hémon from prison, imprisoned for a strangely similar case.