简介：　　Asastringofbrutalmurdersplaguethecity,twoundercoverdetectivesracetosolvethemysteryandunmaskthekiller.Theironlyclues:eachvictimisaformercopandeachhasablood-redletterpaintedontheirbody.Howmanywillhavetodiebeforethekillerspellsouttheirmessageinblood?