Sachie Wakamura just lost her mother, and her estranged grandfather has shown up to take care of her. The only problem is that grandpa is the head of a yakuza gang! Too scared to join her new family, Sachie tries to continue living her normal life. She can't run far though, since one of the most popular guys in school is part of her grandfather's gang and her new protector. No one at school knows about Rakuto's hidden life, and soon Sachie finds herself falling for her bodyguard. But she's the granddaughter of Rakuto's boss, and he can never show his feelings for her. Can Sachie find a way to fit into her new family and grab her chance at love?

The class president asks Sachie to host this year's Christmas party at her house, so she obliges with much trepidation. Even if Sachie hides all traces of yakuza away from sight, will her classmates still manage to find out her secret?