Two girls named Nana meet on a train to Tokyo. Nana K. aims to reunite with her boyfriend and Nana O. hopes to make it big in the music business. Despite their differences, the pair hit it off and become roommates.

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.