Mio, stuck with her father's debt, finds herself at a dead-end when she runs into her first love, Yamato Kujo. She's surprised when she learns that he's become a lieutenant for the Yakuza, and he's willing to take on her debt in exchange for her hand in marriage! The two begin to live together, and Mio finds herself wanting to know more and more about Yamato. It's when Yamato invites Mio out on their very first date, that she learns about Yamato's past...