(15+) In an alternate future, a girl named Arisu is the heiress to the Noirdatter family. Ever since her parents's death, the city state has been at peace which has made the Noirdatter Agency halt its activity. But one day, an event comes to pass that will revive the agency in ways never expected. With her female butler Kindallis at her side, will Arisu still remain sane as her fate unravels? Or will she become the morbid corpse that horrific villains so greedily desire?