Kawana siblings lost their parents when they were young. Her older sister Airi graduated from junior college and became an office lady. On the other hand, her younger brother Tatsuo was playful and didn't study well, but Airi loved Tatsuo, her only family. One day, a yakuza member named Kawagoe contacts her Airi's mobile phone. "Your younger brother made a mistake on our group's sister." Eventually, Airi will be laid down by Kawagoe and others in order to make her comeback. She is even in front of her fiancé because of her brother's betrayal...
