Toppo Jijo, a space-faring mouse from the distant year 2,388,400, accidentally crash-lands on present-day Earth via spaceship, stranding him far from his time. As the first mouse astronaut to traverse the Milky Way, his displacement highlights a stark cultural-temporal divide.

Physically distinct with blond hair, oversized ears, and pronounced anthropomorphic traits, he navigates Earth with snarky mischief, particularly provoking the cat Megaro through size-based taunts. Despite this penchant for trouble, his kind-hearted core fosters cross-species bonds. Uniquely among animals, he communicates directly with humans.

Adopted by human girl Gina, he builds a social circle including local mice—the rotund Pierre and lanky Kurt—and Gina’s hamster Mimi, who champions hamster superiority. Confused by Earth’s ingrained mouse-cat rivalry absent in his era, he clashes with Megaro’s minions, Arro and Braccio, yet remains open to alliances with benevolent cats.

His days involve foiling Megaro’s schemes through wit, aided by friends or chaotic luck, echoing comedic predator-prey chases. He occasionally bristles at perceived discrimination, like human-imposed restrictions. Retaining future-tech prowess—notably spaceship piloting—he endures a fish-out-of-temporal-water existence, adapting to an alien epoch.