It all began with a simple seaside vacation, a brother and sister recapturing their childhood. Antoine Rey thought he had the perfect surprise for his sister Mélanie’s birthday: a weekend by the sea at Noirmoutier Island, where the pair spent many happy childhood summers playing on the beach. It had been too long, Antoine thought, since they’d returned to the island—over thirty years, since their mother died and the family holidays ceased. But the island’s haunting beauty triggers more than happy memories; it reminds Mélanie of something unexpected and deeply disturbing about their last island summer. When, on the drive home to Paris, she finally summons the courage to reveal what she knows to Antoine, her emotions overcome her and she loses control of the car.