1944. In France, devastated by the German occupation, part of the population resists the yoke of the occupiers, men and women who become heroes despite themselves by becoming active members of the Vaucluse resistance. Mother Madeleine, head of an institute for deaf girls, is one of these heroic women. She hides Jewish children and members of the Resistance in her convent, in defiance of the German threat.

Seven-and-a-half-year-old Lio grows up in a fragile family, a precarious balance that increasingly worries her and plunges her into strange dreams where imagination and reality merge. When the announcement of an impending storm strangely coincides with one of her dreams, Lio finds herself alone facing her anxieties and the urgency of the situation.