1970s, six-and-a-half-year-old Sébastien is a sensitive, highly imaginative child. Despite the affection he feels for his father, a dreamy inventor, he notices his mother's loneliness and how there is a lack of love in her life. When they move the house, it won't be long before he sees in Philippe, his new neighbor, an ideal Prince Charming for his mother.
| Actor | Role |
|---|---|
 Nathan GeorgelinSébastien | Sébastien |
 Jacques GamblinThe father | The father |
 Emmanuelle BéartMarie, the mother | Marie, the mother |
 Stefano AccorsiPhilippe Martin | Philippe Martin |
 Audrey DanaMichèle Martin | Michèle Martin |
 Sacha BriquetThe grandfather | The grandfather |
| PPierre BertreThe brother | The brother |
 Hervé SogneGilbert | Gilbert |
| MMyriam MullerL'institutrice primaire | L'institutrice primaire |
| JJulien LandaisChristophe | Christophe |
 Massimo BrancatelliL'ami de Michèle et Philippe | L'ami de Michèle et Philippe |
| DDaniel PlierHerbert | Herbert |
| NNicolas QuijadaFranck | Franck |