Iroha showered her son with love and affection, and before long, they had become a couple. This was the first time that mother and son went on a trip together, and they visited a quiet hot spring inn. They entered the inn, holding hands and talking happily. Then, some suspicious men appeared from the shadows, and they also entered the inn. When the son entered the room, he tried to embrace Iroha, saying that they could make love to each other alone, but Iroha told him not to, and they headed to a private hot spring first. As soon as he got in the bath, his son wanted Iroha, and she smiled and embraced him gently, and they began to desire each other. The men secretly filmed the scene. The subordinate said, "That mother and Iroha are really strange," and asked his boss if he would report it immediately. Yes, they were detectives. The husband, suspicious of the relationship between his wife and son that was more than just parent and child, had requested them to come along with the trip. When asked again by his subordinate what they were going to do, the boss smiled and said that since they had come all the way, they might as well join in. The mother and son, who still didn't know what was going on, were enjoying their time together...