Rika, a female college student, has to find out if her best friend's younger brothers are virgins. First, she checks with her older brother, who is her tutor, and he begs her to get rid of her virginity. Rika is weak to pressure, and although she is confused, she accepts, but he is actually a non-virgin man with an incredible libido! She climaxes repeatedly in agony from the unexpected hardcore sex, and is tricked into thinking she is a virgin by his younger brother, who is also an incredible libido, and makes her cum over and over again!