Seeking to salvage their foundering marriage, Melanie and Richard retreat to an isolated beach house on a remote Queensland island. Intrigued by a chance encounter with a stranger, Melanie begins to drift away from her husband and towards Helena, only to discover that Helena has her own demons, ageless and steeped in blood. As Richard’s world and Helena’s collide, Melanie must choose which future she wants, before the dark tide pulls her under … forever.