When his mother dies and his father remarries, Kaito takes a shine to his sexy new stepmother, Sayoko. Driven mad with lust, Kaito is soon spying on her and sneaking into her bedroom for some covert late-night action. Though racked with guilt, Sayoko eventually finds herself a willing participant. And when Kaito tells her that his father is cheating on her with a younger woman, theirs becomes a full-fledged affair. The sex, sin and betrayal will turn Kaito's whole household upside down!