The Kawana siblings lost their parents at a young age. The sister, Airi, graduated from junior college and became an office lady (OL). On the other hand, her brother Tatsuo had a habit of playing around and didn't study much, but Airi cherished him as her only family member. One day, Airi received a call from Kawagoe, a yakuza. 'Your brother messed up our boss's woman.' Soon, to settle the score, Airi was overpowered by Kawagoe and his crew. Furthermore, due to her brother's betrayal, even in front of her fiancé...
