During her sister's and brother-in-law's trip, Yasuko agreed to look after her three nephews. She had always doted on them since they were little, and her affection for them hadn't changed. Of course, they all slept in a row by the river. However, one night, Yasuko woke up to a shocking transformation: all three brothers had grown into men with large penises. Despite considering them her nephews, Yasuko, driven by her unmet desires, secretly tasted one, then another, comparing their flavors. She then mounted the one she chose and writhed in pleasure, not knowing that Ippei had witnessed the entire scene.
