Despite the opposition of those around her, Mirei raised Tatsuaki as a single mother. Tatsuaki grew up healthy and graduated from university, but instead of finding a job, he continued to work part-time and lived at his parents' house. One night, Mirei woke up to the touch of her body. After that, Tatsumei's pranks continued, and Mirei, who thought that this was not right, planned her trip to the hot springs to have a frank talk with her.
