Follow the summer of Billie's 16th birthday, a lifeguard at the water park, with her two best friends, Rosine and Juliette, as well as her perfect big sister, Annette. Billie's summer is quickly turned upside down when she falls in love with a charming cycling champion.

On December 23, the holiday season is in full force and the destinies of strangers intertwine: a hardened bachelor wants to find love; a couple expect their first child; a singer returns to the stage after a break; a mother tries to organize the perfect Christmas; a teen carries a big secret; a man struggles with the modern world; and the new manager of a large hotel must prove her worth.