Breastfeeding wife next door

I've been working for 40 years, sacrificing time with my family. A ``hot spring trip'' planned by Akio, who has recently reached retirement age, and Taro, the husband of his daughter Fuyumi, to honor Eiko, who has continued to support her husband. The group arrives at a hot spring town, filled with gratitude for Taro and excited about the family trip that Akio never got to go on during his active career. Eiko arrives at the inn and immediately soaks in the hot springs with Fuyumi. However, a man looks at Eiko's body with suspicious eyes. Who is that man...! ?