One morning in May, a brutally mutilated male corpse is found on the shores of the fjord in Gothenburg. Who is the deceased? The police fumble in the dark for a long time until they come a step closer to the eerie murderer through an unusual tattoo on the victim's armpit. Inspector Irene Huss's investigation eventually leads her to Copenhagen, where a prostitute died under similar circumstances two years earlier. Is this a serial killer? One thing is certain: the unusually brutal murderer seems to follow Irene Huss like a shadow.