Marguerite is a young and brilliant mathematician, the only girl in her class at the ENS, entirely devoted to her passion. The day she discovers an error in her thesis, she is devastated. In a dizzy spell, she leaves the school, wipes out the past. She then dives into the real world, discovers autonomy and befriends the young Léa. Grown by her experiences, it is in this new momentum that she will find the solution to her theorem.