Dunno finds a stone on the street and believes that it fell from the Moon. He gives it to Know-It-All. The next day, Know-It-All notices that when the stone is exposed to a magnetic field, it creates weightlessness. Know-It-All decides to build a rocket and fly to the Moon together with the other shorties, after first arguing with the astronomer Glassy about whether there is life on the Moon or not. Before the flight to the Moon, Dunno steals the weightlessness device and almost drowns it in the river.