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.

Anna’s and Thomas’ bandmate was not supposed to die, and Anna was not supposed to kiss Thomas in the aftermath. Nor was she supposed to leave everything and move to Berlin, and Thomas was most certainly not supposed to just show up in Berlin one day, when she’s gotten a new life and moved on from him. But music has its own way.