While secretly longing for a child without her husband's understanding, Marina carries her restless emotions alone each day. One day, her brother-in-law, Takeyuki, suddenly returns home. A man who enjoys womanizing, he senses Marina's hidden desires. Though she resists at first, determined to keep things from going further, Takeyuki's persistent and meticulous foreplay gradually opens her body. Her vaginal walls are worn thin by intense thrusting, her body increasingly deepened and awakened. Before long, Marina becomes helplessly addicted to the pleasure with her brother-in-law, growing dependent on his presence.