Hiroyuki, newly married, started living with his wife Yumi's parents. However, a few days ago, he was seen interacting with a male colleague, causing Yumi to give him the cold shoulder. Trying to make amends, Hiroyuki speaks to her through the shower door... but upon opening it, he finds his mother-in-law Mari there! He hurriedly apologizes, but what catches his eye is Mari's ample and lewd breasts. Never could he have imagined that his placid mother-in-law had such obscenely large breasts. Hiroyuki had opened a forbidden door...
