On a sunny day, a grand B-level gourmet carnival was held in Kasukabe City. Nohara Shinnosuke (voiced by Akiko Yajima) was very excited after seeing the news, so he agreed with good friends such as Sakurada Nini, Kazama Toru, Dai Quanlin, Sato Masao, etc. to secretly go to the carnival to enjoy a feast. At the same time, the news of the B-level gourmet carnival was also spread to the so-called A-level gourmet organization. The highest person in charge of the organization, Mr. Man Gourmet (voiced by Yuichi Nakamura), was full of contempt for B-level food, and he decided to completely destroy these inferior foods. Not long after, the A-level gourmet spaceship flew to the carnival and ruthlessly expelled the bottom-level cooking craftsmen. In order to save the B-level gourmet, Jian decided to use the secret sauce that has been passed down for fifty generations. Jian's lover Hongzi was desperate and handed the sauce jar to everyone in the Kasukabe Defense Force. Shin-chan and his friends inadvertently took on the responsibility of surrounding the B-level gourmet...