Sonia Bergerac is a teacher at a school for difficult children. The problems she encounters in her new workplace are compounded by her husband's decision to leave her. Before long, she is teetering on the edge of a nervous breakdown. One day, Sonia comes across a gun in one of her pupil's school bags. Surprised, she grabs it, and amidst the confusion, she accidentally fires a shot, wounding a pupil. In spite of Sonia's protestations, the commotion soon turns into a veritable hostage drama.