After unexpectedly acquiring an aphrodisiac, a man secretly gives one drop a day to the stepsister-in-law who lives with him. Over the week she grows feverish, sweaty and sensitive, swaying her hips and moaning at the slightest touch. When he catches her unable to resist masturbating, she sees his erection, loses control and eagerly sucks him. He squeezes her big tits and pounds her soaking pussy until she shows a dazed orgasm face and cums repeatedly, then keeps filling her with creampies until pleasure has broken down her resistance and made her completely submissive.