17-year-old Seiji has never dated a girl in his whole life. A notorious brawler, everyone fears Seiji as he can knock down any opponent with one blow of his right hand. Every attempt to ask a girl out ends up in total failure as all girls simply fear him-except for Midori. Midori is the only a girl who sees Seiji for who he really is and although she has been in love with him for a long time, she has not been able to bring herself to convey her feelings to him.
Seiji's loveless life is about to change when Seiji's desperate wish to have a girlfriend and Midori's strong feelings for Seiji manifest themselves in the strangest way possible. Midori's soul merges with Seiji's right hand-the hand feared by everyone as the “demon's hand”.
Seiji and Midori's slapstick love comedy unfolds as they start their strange life together, trying to keep secrets about Seiji's right hand from people.