"Flash! Kimengumi" is a comedic manga series centered around the misadventures of a group of eccentric middle school students who form the Kimengumi, a club dedicated to solving bizarre and often absurd problems. The story primarily revolves around five main characters: Kibe, the self-proclaimed leader with a knack for over-the-top schemes; Marui, the perpetually hungry and gluttonous member; Dekapan, the mechanically inclined but socially awkward inventor; Chonbo, the dim-witted yet good-natured muscle of the group; and Menko, the smallest member with a sharp tongue and a penchant for mischief. Together, they navigate a series of outlandish situations, often involving their school, classmates, and the peculiar world around them.

The narrative is episodic, with each chapter presenting a new, self-contained scenario that showcases the group's unique dynamics and comedic antics. The Kimengumi frequently find themselves embroiled in ridiculous predicaments, ranging from attempting to win a school competition through unconventional means to dealing with strange inventions gone awry. Their solutions are often as absurd as the problems themselves, leading to chaotic and humorous outcomes. The humor is rooted in slapstick, wordplay, and exaggerated character traits, with each member contributing to the group's collective ineptitude and charm.

Throughout the series, the Kimengumi interact with a colorful cast of supporting characters, including their long-suffering teacher, who often becomes an unwitting participant in their schemes, and various classmates who either aid or hinder their efforts. The manga thrives on its fast-paced, gag-driven storytelling, with a focus on over-the-top humor and situational comedy. The characters' exaggerated personalities and the absurdity of their adventures create a lighthearted and entertaining narrative that appeals to fans of comedic manga.