Derek and Bruno spend their days wandering the city, killing time with harmless mischief and reckless decisions. When Derek unexpectedly comes into possession of a handgun, what begins as a game slowly turns into something far more dangerous. As the day unfolds, the line between innocence and responsibility begins to blur. One tragic mistake changes everything, forcing Derek to confront the consequences of his actions and the weight that follows them. "L'ombre de l'arme" is a coming-of-age drama about responsibility, guilt, and the moment when reality can no longer be treated like a game.