Reiko is a single mother raising her son while running a soba restaurant. Her son, now a university student, spends all his time playing and never helps with the business. Seeing Reiko so busy, his friend Shiro offers to work part-time at the shop. While Shiro wants to be helpful, he secretly projects his mother's image onto Reiko and harbors a twisted desire for her. After giving Reiko a Mother's Day gift at the end of his shift, Shiro can no longer suppress his overflowing lust...