Chloé, a pre-teenager, spends her holidays with her mom and her little brother Emil. Since mom and grandma continuously argue, Chloé has to watch over Emil, but he disappears. To find him, grandma will lead Chloé to a mysterious island, that hides in the middle of her pond. The island was built by the family's imagination, when mom was still a kid. But today, it's slowly sinking.To save Emil, the whole family will have to come to terms with their history, and reconnect with their imagination to make the magical island rise again.