Six months ago, Shihori began living with her daughter and son-in-law. Lately, she's been hearing the sounds of the couple having sex late at night, and her body has gradually grown hot with arousal. One evening after dinner, while Shihori was napping in the living room, the young couple suddenly started having sex right in front of her. Not wanting to make things awkward, Shihori pretended to be asleep. But after they finished and her daughter fell asleep, her son-in-law whispered, "Are you awake... Mother-in-law?" and reached his hand toward her body. Unable to resist, Shihori gave in to him. After that night, she realizes what she's doing is wrong—but strangely, she finds herself increasingly drawn to her son-in-law's cock, her desire growing impossible to control...