Upon the cliffs of a remote Scottish island stands a deserted lighthouse. Strange and terrible events have happened here. It started with a witch hunt. Now, centuries later, islanders are vanishing.

A lost family. Liv Stay and her children don't believe in witches or curses. But within months of arriving on the island, her daughter Luna is the only one of them left.

An impossible child. Twenty years later, Luna's missing sister turns up out of the blue. She is exactly the girl Luna remembers. Same face.

Same smile. Same age. Faced with the impossible, it's up to Luna to find out what really happened at the lighthouse all those years ago.