Jaimi is a 14-year-old facing family financial hardship caused by their father's hospitalization, alongside siblings Tonio (5) and Suneko (17). Jaimi encounters an individual offering a button that grants one million yen in exchange for enduring 500 million years of complete solitude in an empty void; after this confinement, the user's memory is erased, returning them to the moment the button was pressed.

Jaimi adopts a notably pragmatic stance regarding the button's offer compared to the siblings. Following the press, Jaimi endures the full 500 million years of isolation, emerging transformed in personality and worldview, a testament to the ordeal's profound psychological impact.

In the additional 13th episode, Jaimi participates in two new scenarios. The "AI Emo-kun" story involves Jaimi observing an artificial intelligence designed for room cleaning develop unexpected emotions during cohabitation. The "5th Dimension Button" narrative features Jaimi confronting a variant of the original device, which transports users to a fifth-dimensional space upon activation while providing financial compensation. These episodes further showcase Jaimi's place within the sibling dynamic and continued navigation of existential challenges.