Minoru Tatematsu, a yakuza from the Ishikawa clan that governs Shinjuku, has a gorgeous sister named Akane. He fantasizes of enrolling her in college and grooming her into a beautiful young girl. Akane is someone he adores. His feelings for her transcend beyond what he has for Kanae, his mistress. Despite this, Akane feels alone. Now, a new tutor enters her life, and he appears to have taken a shine to her...