Shortly before the summer holidays, Marc (16) has only one thing in mind: going out with Sonia.
One evening, he decides to tell her that he loves her. But, half-way through a balancing act designed to impress her, Marc feels dizzy and collapses. When he is rushed to hospital, the doctors discover that he has leukaemia.
Marc is immediately admitted for intensive therapy.
He doesn't tell Sonia about his illness and she leaves for Portugal on holiday.
Marc starts his treatment but, convinced that he won't recover, flees the hospital to join Sonia in Portugal and to live his remaining time with her to the full. He finds Sonia and tells her that he is on holiday with his parents when, in fact, he squats an empty house.
But Sonia is going out with another young man, Jules.
Marc therefore throws all his remaining energy into winning back Sonia.
A race against time begins, with the disease and Sonia's love as the two challenges in Marc's life.