Takashi, a virgin, hears from a friend that women also have sexual desires and masturbate. Out of curiosity, he gives his older sister, Minori, a large dose of an aphrodisiac. At first, his plan succeeds, and he manages to watch Minori masturbate in her aroused state. However, the drug works too well, and Minori, losing herself to lust, discovers him, grabs his cock, and takes his virginity. With their parents away and nowhere to run in their own home, Takashi is repeatedly attacked by Minori, who has become an insatiable nympho, and is squeezed of every last drop of cum until the drug wears off...
