Under the effect of a hallucinogenic drug, Gabriel and his best friend Yves break into a deserted house in the middle of the night, which they ransack. Caught in the act by a neighbor alerted by the noise, the two boys in their last year of high school accidentally cause his death while trying to flee. The next day, noting that no lead links them to the crime, they sign a pact of silence. Shortly after, Yves, the son of a divorced doctor, left St-Hyacinthe to take the entrance exams to a firefighting school, where he was admitted. For his part, Gabriel, first of the class brought up by a single policewoman, sinks into distress and remorse. He renounces his budding love for a classmate and suffers from mononucleosis, jeopardizes his school year. His last lifeline: to go find Yves in order to convince him to break their pact and let the truth come to light.