On her death bed, Kousaku Sakamoto's mother tells him that after she dies, he should go to Tokyo where he'll be taken care of by her friend Ibari Oozora and his family. Since his father died three years before and with no where else to go, Kousaku decides to go along with his mother's last request. However, he soon discovers that Ibari is the boss of the Oozora Group mob ring. Uneasy about his predicament, he considers leaving, but he has second thoughts when he meets Ibari's four daughters–Tsugumi, Tsubame, Suzume and Hibari–only to find out that Hibari is actually Ibari's only son. Now Kousaku must not only cope with living among mobsters but also with refusing Hibari's advances toward him.