Shingo Ōhashi, a human student in a school bridging humans and youkai after generations of integration, begins as an unassuming teen until his path collides with Hatoko "Petoko" Fujimura—a hybrid girl wielding unpredictable charm, adhesive skin contact, and molecular invisibility. Their dynamic shifts from intrigued observation to tentative romance as Shingo navigates the chaos of her powers, from comedic mishaps caused by her clingy touch to the vulnerability of her vanishing form.

Tasked with mediating clashes between human peers and paranormal classmates, he evolves from a hesitant bystander to an active peacemaker, fostering dialogue amid cultural divides. While slapstick moments punctuate their days, quieter tensions surface through societal judgment and Shingo’s own fears about Petoko’s flickering presence challenging their bond. His growth unfolds in subtle strides, balancing schoolyard antics with symbolic stakes—learning empathy through shared misadventures, reconciling teenage insecurities with broader struggles for acceptance, and anchoring a fragile harmony between two worlds within classroom walls.

The story confines its focus to their school-centered present, chronicling Shingo’s incremental journey from ordinary adolescence to an inadvertent ambassador in a society still learning to coexist.