Cairo, a reformed criminal, enjoys his new life as a gang exit counselor. When his nephew Hamza disappears, Cairo discovers he had secretly joined his former gang. Despite his pledge to avoid violence, frustration with the police's lack of action pushes Cairo to seek help from his former underworld connections. His investigation leads him into Copenhagen's criminal scene. Despite his efforts to avoid violence, his past instincts resurface.

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.