Rui raised Masaaki as a single mother. Her father already had a legal wife, raising Rui single-handedly and Masaaki going on to graduate school. One day, after raising her children, she was contacted by Masaaki's father for the first time in more than ten years. His legal wife died several years ago, and he was not blessed with her heir, so he offered to take Rui as her second wife. A few days later, she received an invitation from Masaaki to go on a hot spring trip, so she got on Masaaki's car, even though she was worried about her future.
