Nobody at Sakuradamon High hasn't heard the rumors of Seiji "The Mad Dog" Sawamura's demonically strong right hand. His notoriety makes approaching ladies difficult, and after being rejected 20 times in a row, he half-jokingly promises to graduate high school with his right hand for a girlfriend. Seiji realizes, to to his amazement, that his demon right hand has miraculously transformed into a little girl, Midori Kasugano, who discloses that she has had a crush on Seiji for the last three years after waking up the next morning. Seiji tries to bring Midori to normalcy because their condition isn't optimal for either of them. However, after provoking a major misunderstanding within the Kasugano home, the duo parted ways.