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?
A new school year starts, bringing a new teacher to Sachie and Rakuto's class. He seems to be a breath of fresh air and enthusiasm. But he has a secret past and harbors a wish for revenge against Sachie. Now he threatens to reveal Sachie's family secret and have her run out of school!