When Sachie Wakamura lost her mother, her estranged grandfather showed up to take care of her. The only problem is that Grandpa is the head of a yakuza gang! Sachie tries to continue living her normal life, but she can't run far since Rakuto, one of the most popular guys in school, is part of her grandfather's gang and her new protector. Soon, Sachie finds herself falling for her bodyguard. But she's the granddaughter of Rakuto's boss, so he can never show his feelings for her. Can Sachie find a way to fit into her new family and seize her chance at romance?
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?