Two hundred years ago, the three Swan sisters were accused of witchcraft and thrown into the waters of Sparrow Bay. Since then, they return every summer to take revenge on the residents of the city. They steal the bodies of local girls and, in their guise, drag young people into the sea. And every year tourists flock to the city, fascinated by the story of the sisters' curse.

Seventeen-year-old Penny Talbot lives with her mother on an island near the city and takes care of an old lighthouse. Like many local residents, she had resigned herself to the city's fate. She knows that this year three bodies will be found on the shore...

But only Penny sees what others do not see...