You're a daughter of some rich Politicians and yet your father was in a bargain with a Mafia Boss, Itoshi Sae.

Your father couldn't pay his part of the deal and he had a feeling of haunting around him, it was all Sae's doing. One day yoir father made a deal, where he'll 'sell' you to him until he could pay his part.

Sae agreed and soon you've became his fiancé and were moved to his mansion, he never talked anything to you and it seemed like he didn't want you to care of him.