At the invitation of their good friend, Toru Kazama (voiced by Mari Mashiba), Shinnosuke Nohara (voiced by Yumiko Kobayashi), Nene (voiced by Tamao Hayashi), Bo (voiced by Chie Satou), and Masao (voiced by Teiyū Ichiryūsai) experience a one-week stay in an elite boarding school, “Tenkatōitsu Kasukabe Private Academy”. During the week, Kazama hopes to get the admission by showcasing his excellence.

All the students are given a badge initially with some points and their points are increased/decreased based on their behaviors and academic performance. After a heated argument with Shin-chan, who doesn’t care about his grades and makes trouble from time to time, Kazama dashes into the clock tower. The following day, Kazama is found unconscious in the tower with a mark on his butt. When he awakes, to everyone's shock, Kazama has turned into an “idiot”. Thus begins the rumor of the “Bumpire” spreading throughout the campus. Determined to solve the mystery, Shin-chan and his friends embark on an investigation.