A woman jumps into her car, her hands bloody as she grips the steering wheel. With her young son in the back seat, she flees to the only safe place she knows: the island of Gråskär outside of Fjällbacka.

A couple of days later, a man is found murdered in his flat. Mats Sverin was the council's financial director and nobody has a bad word to say against him. But when detective Patrik Hedström and his team start looking into his life they uncover a number of shocking secrets.

It turns out that the man had visited Gråskär before he died. Locally the island is known as Ghost Isle; they say it's haunted by the dead and that they have something to tell the living...