When weird masked raiders attack a United States spaceport, Tom's plans for his latest space exploration project are jeopardized. The project would launch astronauts on a newly sighted planetoid for an epic voyage around the sun. First, Tom must prove that his latest invention, the Duratherm Wing, can bring reentering spacecraft safely down to earth. A fiery mishap on the test flight is only the beginning of Tom's troubles. Fake evidence results in the young scientist-inventor being accused of masterminding the spaceport raid.

In the meantime, another small planet has been mysteriously captured by earth's gravity. On an expedition to the strange planetoid, Tom discovers a fantastic prize. But grim developments follow. The planetoid is sinking into the atmosphere and threatens the continent of North America with the most terrible catastrophe in history!

How Tom meets this challenge with high courage and scientific know-how, and how he outwits his insidious enemies, will bring cheers from his worldwide legion of fans.