In a small Japanese town, an eccentric inventor has been working on a revolutionary experiment: a machine that can make anyone invisible. However, things get complicated when his neighbor, a lonely and somewhat perverted young man, decides to test the invention. With his new ability to become invisible, he feels empowered and ready to uncover the hidden secrets of his community, especially those of the women in the neighborhood.
His first stop is the local onsen, where his curiosity is ignited, and he finds himself caught up in a world of comedic and absurd situations as he sneaks into the women's bath. As he delves deeper into this new "invisible world," he becomes an expert in the art of spying. However, his uncontrolled curiosity soon leads to unexpected chaos. The atmosphere of fun becomes clouded when the women, terrified by suspicions of an invisible stalker, begin to band together and investigate who might be responsible for the intrusions.
The invisible boy finds himself in an increasingly complicated situation, torn between the desire to experience the freedom that his invisibility offers and the danger of being discovered. He almost feels guilty about his behavior but is unable to resist the temptations. As the story progresses, he will be forced to confront his own desires and the ethics of his actions, in a comedy that combines humor, social criticism, and a touch of sensuality.