In a system that has always let him down, Morville, a young loner in his thirties, has become Vigilante. He traps pedophiles by pretending to be a child on social networks. His goal: to expose them and ruin their lives.When one of his friends, also Vigilante, is brutally attacked, Morville once again decides to take justice into his own hands. He plunges further into a dark universe which will confront him with former prey and the police who despise the Vigilantes. Faced with the collateral damage of his actions, Morville is confronted with the morality of his own justice.