Bokan ~Kaa-san no Naka wa Dare no Mono?~

The protagonist, Ueshima Haruto, was living alone with his stepmother Ruriko in an apartment. Despite being his stepmother, Haruto has developed romantic feelings for Ruriko, who is kind, domestic, and beautiful. One day, he witnesses her masturbating while thinking about her deceased husband. Unable to resist, Haruto also masturbates on the spot. When he was about to be found, he hurriedly fled the scene, but Ruriko understood the situation from the smell of the semen that remained on the spot.
She is troubled after learning that her adopted son is aware of her as a member of the opposite sex. To her doorstep comes her father-in-law, Gouzou, who has been waiting for an opportunity to embrace her. Gouzou skillfully draws out Ruriko's worries and makes her a proposal. The proposal is for Ruriko to find another man in order to give up her feelings for Haruto. Gozo pushes the bewildered Ruriko onto the sofa and forcibly engages in a physical relationship with her. Ruriko desperately resists, but is brought to climax many times by Gouzou's skillful technique, and finally ends up creampied. After Gouzouu left, Ruriko cried tears of sadness for being betrayed by her trusted stepfather and guilt towards her husband. However, deep inside that body covered in semen, the pleasure of a woman that had long been forgotten remained as a hot throb that continued to linger...