"Gakkatsu!" is a short-form anime series that revolves around the daily lives and humorous interactions of a group of elementary school students. The narrative primarily takes place within their classroom, where the students engage in a variety of quirky and imaginative activities during their free time. The series is episodic, with each episode focusing on a different scenario or game invented by the children, often leading to absurd and comedic outcomes.

The main characters include a diverse group of students, each with distinct personalities that drive the humor and dynamics of the series. Among them is the energetic and mischievous leader, who often initiates the group's activities, and a more reserved but equally imaginative classmate who contributes creative ideas. Another key character is the class representative, who attempts to maintain order but frequently gets swept up in the chaos. The teacher, though occasionally present, remains largely oblivious to the students' antics, allowing the children's creativity to take center stage.

The plot of each episode typically begins with a simple idea or game proposed by one of the students, which quickly escalates into a series of exaggerated and surreal events. These scenarios often involve imaginative role-playing, such as pretending to be explorers, detectives, or even aliens, with the children fully committing to their roles. The humor arises from the contrast between their earnestness and the absurdity of their situations, as well as the playful banter and misunderstandings between the characters.

Despite its comedic tone, "Gakkatsu!" occasionally touches on themes of friendship, teamwork, and the boundless creativity of childhood. The series captures the essence of elementary school life, where even the most mundane activities can become extraordinary adventures through the lens of a child's imagination. The brevity of each episode, combined with its lighthearted and fast-paced storytelling, makes it an accessible and entertaining watch for audiences of all ages.