The Sakurai siblings lost their parents at a young age. The older sister, Mami, continued to work hard, graduating from junior college and becoming an office lady. She now has a husband and is living with her younger brother, Masato, who is busy studying for his entrance exams. Mami and her husband Ke'ai Masato, their only family, very much. One day, they receive a call from a man named Takimoto. He says, "Your younger brother ruined the boss of our gang." To settle the score, Mami and her husband are called by Takimoto and his men...