Hiroshi, the only son whose father has remarried a woman under the age of 20, and has decided to live with her mother-in-law, Akari. Hiroshi tended to withdraw from work without being fragile, but he couldn't hide his excitement in his life with Akari, who was only five years old. One day, while cleaning, the excitement of the panties glancing through the skirt of Akari greets Max. From that day on, Hiroshi was watered down by the fascinating charm of Akari.