Yokoyama is at his wife's parents' home when she is about to give birth, and is attracted to the voluptuous body and behavior of his sister-in-law Minami, who has grown into an adult woman, and is disturbed. He is looking forward to peeking at Minami with a camera he borrowed in the name of security, but when he witnesses Minami's lewd appearance as she takes a male subordinate into her room and shakes her hips to devour pleasure, her suppressed desires begin to swell. A must-see is the realistic rape scene in which popular busty actress Minami Ayase makes her first appearance on Madonna, resisting the rape and feeling it!