The daughter and son-in-law wanted to save money to buy a house, so they moved in with their mother-in-law. Maiko used to be a photo model, and she had no idea that her son-in-law was a fan of hers.

One day, Maiko accidentally discovered that her son-in-law was watching a sex movie with an actress who looked a lot like her, surrounded by photos of her when she was a model.

He used her photo to masturbate his son-in-law's big dick, making Reiko unable to take her eyes off him.

It turned out that the dick was so big that it hurt Maiko's daughter. It had been a long time since her son-in-law had sex, so he had to "take care" of it alone. Feeling sorry for her son-in-law, Reiko decided to offer to "take care" of his big dick instead of her daughter. At Maiko's invitation, plus the fact that he had suffered for so long, he could no longer resist. From then on, the two continuously secretly fucked each other whenever they had the chance, secretly maintaining this wrong relationship...