One day, Yusei, a son who doesn't think well of Mako, whose father remarried and became a new mother, forcibly rapes Mako and films her with his smartphone, using it as a material to threaten Mako and train her to become a tit-fuck sex slave. Yusei's training escalates, and while her father is away, he and a DQN senior restrain her and make her cum with an electric massager and a vibrator, and then he fucks Mako's big boobs with a senior with a big dick. Mako gradually went crazy as well.