"Is the Earth really spinning? And who was the first to notice?" Maruko suddenly wonders. People in the past believed that both the sun and the stars revolved around the Earth, but it seems that figures like Copernicus and Galileo discovered that it is actually the Earth that orbits the sun. Wanting to learn more about the Earth and the universe, Maruko and her friends decide to visit the science museum. There, they come across the strange visions of the cosmos imagined by ancient people...!?