One day, a woman named Chiyome Hesogakure with a child named Chinzō visits the Nohara family and claims that she is the real mother of Shinnosuke and takes him away…
When the five visit a private academy, Kazama is attacked, and left with reduced intelligence and strange bite marks.
When the mysterious Shiriri turns his parents into children, Shin-chan must trek across Japan to help return them to adult form.
A diabolical plot to empower pushover dads causes Shin-chan’s father to return home as a robot. The Nohara family bond is about to be put to the test!
Shin-chan must rescue the adults of Kasukabe when they mysteriously abandon their responsibilities to relive their youth at the new 20th-century expo.