Mitsuko, who lived alone in the countryside, moved in with her son and his wife who lived in the city. Although it was a lonely life, Mitsuko couldn't help but be happy to be living with her son and his wife. Six months after they started living together, just when they were getting along well, Mitsuko was pushed down by her son. Mitsuko's sexual desire grew stronger with each passing year, and she was comforting herself almost every day. Her son saw her doing so. Her son caressed Mitsuko roughly and plunged his penis into her. Mitsuko was reluctant, but her son didn't stop, and he released hot milky liquid from her body. A few days later, Mitsuko's wife confided in her that they hadn't had sex recently, and she was confused, thinking that it might be her fault. Just then, Mitsuko's period ended...