Yuan is reincarnated in the setting of a romance novel he read in his previous life. ...Not as the hero or heroine, but as the villain's son of a mob character!! Even so, Yuan is committed to playing the role of the "villain's son" in order to see the happy ending between the fallen hero Calisto, who he has been rooting for since his previous life, and The heroine... but the events with the heroine are a complete failure. He plots to bring the two together, who are still strangers, but things go in an unexpected direction...?! Yuan is worried that he injured Calisto because of his mistake, and he unilaterally expresses his affection for her. Before he can respond to the unexpected advances and courtship, Yuan is forced to have a sex change...! In order to get Yuan, he will destroy the original story...! With his body open and his mind manipulated, will he be driven crazy by the obsessive raw sex of the yandere protagonist...?