This is the story of the adventure of a little boy named Sheldon and his dog, Jet. When Sheldon’s best friend moves away, Sheldon spies the word “Jupiter” painted on the side of the moving truck. Sheldon feels sad at first, but realizes that this is a sign—what he needs is a rocket ship! So Sheldon and Jet do some sketching and some scrounging, and, with a wagon full of equipment and supplies, the two future astronauts head to the backyard. With a glop and a wham, piece by piece the ship begins to take form, and soon it’s Commander Sheldon A. Flyer and Space Cadet Jet ready for takeoff! The duo jets around satellites, zooms by planets, speeds through space storms, and zips past other flying saucers . . . until plop, they’ve arrived, somewhere with a green, alien life-form and a furry black blob.