Tsumugi, though pure-hearted, gradually discovers a perverted pleasure. Curious and eager, she becomes aware of the joy derived from making older men drink her urine, becoming obsessed with this pleasure. "If it makes you happy, Uncle... Tsumugi will give you lots of pee!" she says cheerfully, delighting in the excitement of grown men. Behind her innocent smile, a new desire begins to bloom. Before long, she transforms into a full-fledged dominatrix, fulfilling the desires of adults. Her sacred urine training grows deeper and more intense.