After repeated requests for a meeting from former colleague Christian, who is on the verge of retirement, Detective Carl Mørck sends Rose, his junior colleague in Department Q, to the remote Danish Island of Bornholm in his place.

But when an incident occurs at Christian’s retirement ceremony, Carl, Rose and assistant Assad are forced to unite on the island and against their will become embroiled in a cold case about the murder of a young woman from Bornholm. The case, officially shelved as a traffic accident, has connections to both the local Police precinct and a covert cult of sun worshippers.

Once the case is reopened, the island becomes dangerous, and the team is confronted with their own dark sides…