nami yasumi lives happily with her beloved husband and her daughter's family, but her nighttime life has been neglected, and she has become accustomed to relieving herself with masturbation every night. and so is her son-in-law tsuyoshi, who spends his days peeking at her and comforting himself. nami, who was captivated by his big dick, disturbs his heart and continues to tempt him on every occasion. unable to resist such a mother-in-law's invitation, the son-in-law and she eventually devour pleasure day and night...