Sex, love and obsession are thrown sharply into focus in this darkly sinister film. The so-called stupid boy of the title, Loic is a confused yet sexually liberated young man who divides his time between working in a factory and engaging in random, often paid, sexual encounters with an assortment of men he meets on the internet. However, a developing obsession with his best friend Marie, a non-sexual relationship with the enigmatic Lionel and a lust for a famous footballer whose star is falling, all conspire to drive Loic to the very edge of sanity.