Manga by author Zappa Go

Tsuchie Takeshi has dreams of playing with Hikari-chan as a child. He remembers her as a kind, sweet girl. However, one day on the way home from school, Takeshi is abducted and taken to a huge house, only to find out that she's become an arrogant, violent dominatrix. Furthermore, she says that he promised to marry her! How will he adjust to her new personality, and living with her as a new son of her prestigious family?

As a child, Kawagoe Haruma eagerly awaited the birth of his little sister. However, his mother had a miscarriage, followed by an operation that left her unable to bear children. That Christmas, Haruma made his Christmas wish. It was a wish so innocent and heartfelt that it was accepted instantly, unbeknownst to him.Many years later, on Christmas morning, college student Haruma is awoken by a woman riding a hovering motorcycle and claiming to be Santa Claus. She throws him a bag, and he opens it to find his new little sister!Complaining to Santa Claus that he made this wish a long time ago, she tells him that it takes much longer for a sister than it does a toy car. After naming her Choko because of the Anchoko (mini-guidebook) she carries around, they begin their new life as brother and sister in a crazy apartment building filled with interesting neighbors.