Four friends are spending the night at Lake Bodom, where unsolved murders took place many years ago. The young men are determined to venture into the dense forest to solve the mystery.

In a moment of cowardice, Detective Carl Mørck sends Rose, his junior colleague in Department Q, to the remote Danish island of Bornholm to answer his old colleague Christian Habersaat's repeated requests. But during his forced retirement ceremony Christian kills himself sending Rose into a journey deep into her own traumatic past. Later, Department Q are embroiled into an old cold case of a girl found dead hanging in a tree.

After a surprise invitation, an enigmatic media mogul Dragan Ivanovic returns to his hometown to examine his extremely hostile relationship with neurotic younger brother, as well as brother's new and suspicious romance.