Mathias, 18, is at the age when he has to make choices about his future, while his relationship with the world and those close to him has been turned upside down since he began a gender transition. Blocked by his anxieties, he isolates himself. Until one day a man arrives at his door claiming to be Mathias, fifteen years his senior. Their conversation will help him put into words what he is feeling, and learn to open up to others once again.