Jaimi, 14, faces financial hardship alongside siblings Tonio (5) and Suneko (17) due to their father's hospitalization. They encounter an individual offering a button granting one million yen under one condition: pressing it subjects the user to 500 million years of solitary confinement in an empty void. All memory of the experience is erased upon completion, making it seem instantaneous from their perspective.

Jaimi appears in subsequent stories beyond this initial premise. Later, Jaimi participates when the siblings discover an AI named Emo-kun, which develops unusual emotions while helping them clean their room. Jaimi is also present during an encounter with a "5th Dimension Button," offering a similar financial reward but transporting the user to another dimensional plane.

During a separate adventure, Jaimi joins a picnic expedition to the edge of the universe using a "super tachyon picnic blanket," posing a question about the universe's edge that prompts the scientific endeavor. In another incident, Jaimi investigates alongside the group when time reverts to the past, causing temporal confusion and potential danger.

Jaimi consistently appears alongside Tonio, Suneko, and Dr. Inoue across these varied scenarios.