Rui raised Masaaki as a single mother. His father already had a legal wife, so Rui was raised alone and Masaaki went on to graduate school. One day, after raising her children, she received a call from Masaaki's father for the first time in over a decade. His legal wife had passed away several years ago and he had no heir, so he asked to take Rui as his second wife. A few days later, Masaaki invited Rui on a trip to a hot spring, and although Rui was anxious about her future, she got into his car.