After the death of her parents, Tsukasa turns to her classmate Ryuji, a yakuza boss, for shelter and a job. Ryuji is generally grave, but purposefully indebts Tsukasa to him so that she has to keep working for him, and he can keep his friend near him. Tsukasa is a simple-minded girl who desperately searches for money to pay off her debts to Ryuji. To make money, she takes on suspicious jobs in addition to being Ryuji’s bodyguard, but always ends up in trouble. Ryuji and Tsukasa take turns saving each other as they fight together against the spread of dangerous drugs and weaponry that would destroy Tokyo even more than it has already degraded.