On the idyllic Swedish island of Gotland, another teenager is found dead. This makes 22 suicides in 17 months. There are no notes. No explanations. No reasons. Each new death rocks the island to its core, and everyone holds their breath for the next to be found ...

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With the media ordered not to report on it, the police baffled, and the islanders looking desperately for someone to blame ... chaos is imminent.

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As terror takes root in every home and mind, and the death toll continues to rise, only one thing links the victims: a black heart, etched into their skin. What does it mean? And will it be enough to save the island before it tears itself apart?