While his father is overseas on business, leaving his son Ken behind, Ken is set to appear on the show Muscle Champ, causing his father concern. To ease his worries, a housekeeper is hired—Kaede arrives at the house. However, Ken pays no mind to her presence and continues obsessively training. No matter how hard he works out, he struggles to develop visible abs. One day, by chance, Ken catches sight of Kaede doing housework. Her appearance deeply excites him, and suddenly, he finds himself able to perform perfect sit-ups.