Naoya's intense obsession grants him an exceptional ability to identify individual breasts solely through visual images. This unique skill leads to his recruitment into a mysterious game where he must locate women matching specific breast photographs printed on special tickets provided by the game administrator, Nir or Nil.

His mission requires using these tickets to find and engage in sexual encounters with numerous women across the city – including teachers, sample distributors, and others – to identify five designated "championship breasts." During this quest, he deploys a specialized "scouter" device to isolate and examine breast imagery, though his inherent recognition ability often renders the tool auxiliary.

Naoya progresses sequentially by finding and interacting with women based on the ticket images, many of whom lack names or backstories. These interactions include a disappearing shrine maiden, a childhood friend, and a maid who pledges lifelong service before similarly vanishing. The quest culminates with Naoya expressing a desire for the game administrator, Nir, to remain with him, indicating a preference for continuity beyond the transient connections formed during the game.