One day, the Superhuman Registration Act is implemented, mandating that all superhumans must have their powers inspected and registered by the Association and the government. Superhumans who had been living ordinary lives while hiding their powers protest vehemently, but the government begins labeling all dissenters as villains and arresting them.

Seo Nayoon, an S-class superhuman, is in the middle of a battle against villains opposing the registration. Using her giant-transformation ability, she captures the villains who were wreaking havoc on the city with one hand and hands them over to the Hero Association.

In the middle of a destroyed street surrounded by collapsed buildings where other citizens have evacuated, Yoon Minseok—a civilian and Seo Nayoon's husband—is busy recording her heroic deeds with his camera.