Jaimi is a fourteen-year-old and the sibling of Tonio and Suneko. Their family urgently requires a large amount of money to cover their father's hospital expenses, a pressure that heavily influences Jaimi's decisions.

An individual presents the siblings with a button that promises one million yen to the person who presses it, under the condition that they must then endure five hundred million years in complete isolation within an empty void. After this time elapses, all memory of the ordeal is erased, and the individual returns to the exact moment the button was pushed.

Jaimi grapples with the offer's deep philosophical weight alongside the other siblings. The story delves into their reaction to the deal and the unfolding consequences once the button is activated.

In a later sequel episode, Jaimi joins Suneko and Professor Inoue on an expedition to witness the edge of the universe.