Allserialkillerscommitmurdertosatisfytheirgrandfantasies,butthemurderersfeaturedinTheMarkofaKiller,takeitonestepfurther,committingheinousactsthatallowthemtoextendtheirfantasiesandrelivetheexcitementoftheircrimesagainandagain.Withmanykeepingpostmortemsouvenirsandperformingdistinctritualsduringeachkilling,theirsignaturetrademarksoftenprovetobetheirundoing.Thisseriesfollowsthetrailsoftheirobsession,andtakesadeepdiveintothekillers’depravedpsychestorevealtheirdarkestsecretsasinvestigatorscloseintoendthekiller’sreignofterror.