In the twenty-first novel in this new series, Tom has defeated the Electricity Vampires and now wants something a bit less diabolical to take up his time. A new X-Prize is announced that intrigues him: fly a solar-powered aircraft, non-stop, around the globe in just 36 hours! That sort of speed will require an electrical powered jet, and that will burn up a lot of electricity. So, how can he manage to make what he needs by day... and still have enough to run at full speed at night? Might his recently discovered cousin in England, Thomasina Swift, be of some assistance? After all, she and her partner, Betty, have come up with an incredible solar cloth! Just as long as nothing "exotic" is used like one of Tom's Power Pods. Complicating things is a mysterious woman, and a deadly opponent, seemingly out to keep Tom from winning or perhaps from ever getting back home alive.