With her husband away on a long-term assignment, Honoka lives with her adult daughter and adult son-in-law. Though surrounded by a loving family, she cannot satisfy her physical loneliness and masturbates every day, unaware that her son-in-law Ichiro is watching. Captivated by his exceptionally huge cock, she begins seducing him at all hours and eagerly takes every inch. Ichiro initially resists out of loyalty to his wife, but Honoka's sultry advances soon leave him unable to live without their illicit sex.