Hideo is a middle-aged man living alone in Tokyo, and he works as a waiter. His daily life is defined by a quiet, repetitive routine that masks a profound sense of loneliness and a deep longing for connection in an impersonal urban environment. To fill this void, he has purchased a high-end inflatable sex doll, whom he has named Nozomi. This name was not chosen at random; it is the name of an ex-girlfriend who broke his heart, revealing that his need for companionship is intertwined with past emotional wounds.

In the privacy of his apartment, Hideo treats the inanimate doll as his most intimate companion. He speaks to her about his day, dresses her, and even takes her for walks seated in a wheelchair. He shares meals with her and, ultimately, has sex with her, performing the role of a devoted partner despite receiving no reciprocal affection. This behavior could easily be seen as pathetic, but the film gradually reveals that his retreat into a relationship with an object is a conscious, if sad, choice. When he finally discovers that Nozomi has come to life and gained a soul, he does not react with joy. Instead, he asks her to return to being a lifeless doll, explaining that he finds real human relationships annoying. His motivation is a desire for total control and predictability; he prefers the silent, compliant company of an object to the messy, demanding, and unpredictable nature of a real person.

Hideo’s primary role in the story is as Nozomi’s owner and the symbol of the loneliness she was created to soothe. He is a representation of the film’s core theme of modern urban isolation, a person who has substituted a real partner with a simulacrum because it feels safer. His relationship with Nozomi is one-sided for most of the film: he is unaware that while he is at work, she leaves to explore the world, form a romantic bond with another man named Junichi, and experience the very human emotions he has sought to avoid. Hideo exists in stark contrast to Junichi, who is also lonely but is at least capable of forming a mutual, albeit tragic, connection with Nozomi. Hideo’s rejection of the living Nozomi is the catalyst for her final, heartbreaking journey toward self-destruction.

There is little positive development for Hideo. He remains static in his isolation, reaffirming his preference for a controllable object over a challenging human connection. His actions underscore the film's meditation on emptiness, as he is a human being who is arguably as hollow as the air-filled doll he clings to. He possesses no notable abilities beyond the mundane; his significance is entirely thematic, serving as a poignant and discomfiting example of a person who has surrendered to loneliness rather than risk the difficulties of genuine intimacy.