Accompanied by his extraordinary confidant Doudou, T'choupi discovers with wonder the small village of the seaside where he will live. The beautiful days of summer, the beach, freedom - Very quickly, the holidays are rich in encounters and adventures. He shares with Doudou all the events of his life, where joy and jealousy mingle; the family is growing, T'choupi now has a little sister, Fanny. But a mysterious shadow disturbs the happiness of the village children by stealing their favorite toys. With Pilou and Lalou, his new friends, T'choupi will conduct a thrilling investigation to unmask the culprit.