Crime Inspector Maria Wern returns to duty at the Police Department on the island of Gotland, and is immediately thrown into a murder investigation.

After a young woman and her parents are murdered by a killer determined to wipe out the entire family, Detective Inspector Joona Linna works with a psychiatrist to hypnotize the son who narrowly escaped death in order to find the one surviving daughter before the murderer does.

In the middle of the Medieval fair in Visby the house of a 70-year-old woman is set on fire, and she is presumed dead. When another murder occurs Maria Wern and her police colleagues head for a picturesque summer town where everybody knows each other - and where the discovery of several Latin texts and incomprehensible drawings makes the police suspect that all the events have something to do with the medieval fair.

After intervening in a fight, and because of her own history of being abused and beaten, Maria Wern takes on an investigation of the death of a woman who was murdered close to where Maria was beaten. The motive shifts from revenge for infidelity to hate crime against homosexuals, and when the murders continue, Maria's frustration with neighbours and witnesses who refuse to talk increases.

Two women, with no obvious connections, die in what initially looks like suicides. But the odd circumstances have the Gotland police starting to dig deeper, and soon more questions arise.