Makoto Maegami is a timid fifth-grade elementary school student whose ordinary life takes a wild turn upon discovering Gonjiro, a mysterious red hairball. This encounter begins when Gonjiro consumes one of Makoto's buttons, triggering an immediate transformation into an alien-like form. Gonjiro attaches himself to Makoto, sensing and understanding his feelings, forging an unusual bond.

Makoto's once-structured routine descends into chaos as he's thrust into increasingly bizarre supernatural adventures. Gonjiro actively involves himself in Makoto's predicaments, using abilities like "Fit," "Shapeshift," and "Button Change" to navigate difficult, often "hairy" situations. He morphs his hair-based form to assist or protect Makoto, though these interventions frequently backfire or cause complications. Makoto often views Gonjiro as a significant annoyance due to this unpredictable meddling.

Despite the friction, a connection grows between them. Gonjiro persistently encourages Makoto to release stress and "let it all hang out," and they share a fondness for yakisoba sandwiches. The series chronicles Makoto's experiences entangled with Gonjiro's protective actions across various challenging scenarios. While Makoto's initial troubles stem from his own actions, they increasingly involve supernatural elements introduced through Gonjiro, marking his adaptation to unforeseen circumstances and reliance on this unconventional companion. The narrative centers on their evolving dynamic.