Two siblings, older brother Yoshio who had a bad one leg, and sister Mariko who had intellectual disability lived in one port town. One day, Mariko was gone from home. A while later, She was protected by the angler. When they coming home, 10,000 yen bills find from pockets of Mariko's pants. He heard that, she said had sex with the angler but, she can not understand what is wrong. After that, Yoshio was fired the company. He was in danger of life, so tried to make a living by prostituting Mariko.