Katsu Donbe, a genius elementary school student with an IQ of 300, is a student at Shumei Gakuen, an elite school. However, Donbe is an inferior student with only 0 points!? If he puts his heart into it, he should be able to reach the top... One day, a young girl asks Donbe to build a time machine. The girl has a painful past, losing her older brother in a traffic accident... but can she make a real time machine!?