Due to her husband's work transfer, Kyoka suffers from daily sexual frustration. Reaching her limit, she begins relieving her stress through masturbation. One day, her nephew Yusaku visits to deliver a package. Struck by his strong, attractive appearance, Kyoka feels an intense attraction. Meanwhile, Yusaku has secretly harbored feelings for Kyoka since childhood. As their emotions grow, they enter a phase of mutual masturbation, drawing them closer each day. Caught in a whirlwind of desire, their relationship escalates beyond boundaries.