Traumatised by the death of a child in her care, top London paediatrician Claire seeks refuge on remote Selkie Island in the wilds of the Irish Sea with her husband Daniel and their baby daughter Kitty. Hidden away in Daniel's old family home, Claire hopes to be as cut off from her guilt as she is from the mainland, but can she find peace in a place so full of its own secrets?

Twenty years earlier, Daniel's parents left the island in a boat and never made it to the mainland. Mystery surrounds their deaths-and their lives. Why did they set out late at night in a storm? What had really been going on at the house? Even as Claire begins to recover her sense of self amid the island's rugged beauty, she can't shake off a chilling suspicion that Selkie Island has a dark history that the locals just can't face-and that it somehow has a connection to her own life.

When baby Kitty suddenly disappears, Claire's fragile world falls apart. The only way to secure her future is to uncover the past, but the closer she gets to answers, the more danger she finds herself in. Will she be able to save her family or will the island's dark secrets take another life?