After her supposed death, a young woman returns as the son of her noble family to precede the family's prestigious company, with a demon at her side to avenge her parent's murder.
Set in the year 2020, Shiori Genbo (Ayame Gouriki) runs the large corporation Funtom. Shiori is also a descendant of prestigious noble family Phantomhive of England. As a descendant of the noble family Phantomhive, Shiori solves difficult cases which are ordered by the queen. In order to take revenge, Shiori makes a deal with Butler Sebastian (Hiro Mizushima). Their deal involves Butler Sebastian protecting Shiori until her revenge is fulfilled and then Sebastian will consume her spirit.
