On the afternoon of Christmas Day, a man is murdered in his car. The falling snow covers the victim like a shroud. It is only when the thaw begins that the crime is discovered. The investigations led by Karin Wolf, Sandra König, and their colleagues take them into a horrific swamp of child abuse and extortion. However, Chief Inspector Karin Wolf cannot devote her full attention to the case, as her arch-enemy Witkowski has managed to escape from prison and immediately embarks on a quest for revenge. In the hunt for the criminal, Karin is shocked to discover that a member of her team is working for Witkowski. For the inspector, a fight for survival begins, as she herself is at the top of the killer's list.