Le garde du corps

12-year-old Pierre just can't understand his 15-year-old sister Alex anymore. She's been hiding things from him, she's changing. So he keeps spying on her. One night, when her sister steals out of the house, he decides to follow her without her knowing it. Nothing happens as he had imagined it. Worse, she forces him to come along. It's a chance for them to patch things up.