Haruko's mother, Miho, comes to her for advice, saying that her married life has become dull. Not knowing what to do, Haruko consults her husband, Ikuo, who suggests that they go on a trip to a hot spring together. On the day of the trip... Ikuo sees his wife's family breathing in the unusual air and laughing non-stop, and grins, knowing that the success of the trip is almost in his hands. Ikuo's true purpose for this trip is to seduce his mother-in-law, Miho. After dinner, when Miho gets tipsy, Ikuo immediately takes her into another room...