After losing her husband, Sumire lives alone with her son, Kenta. One day, while she is masturbating alone, Kenta's friend Atsushi happens to catch her in the act. Shocked and overwhelmed by desire, Sumire gives in and takes Atsushi into her bed. That night, her body undergoes a transformation, awakened by new sensations. The next day, other friends who learn of the incident begin visiting one after another. Thirsty and trembling with arousal, Sumire draws each of them in, forging new intimate relationships. Her evolving desires and actions gradually unfold throughout the story.