Ever since his first adventure in his Flying Lab, the youthful inventor had been involved in many daring exploits and thrilling situations. Time and again, Tom had had to combat enemy spies and vicious plotters bent on stealing the Swifts' scientific secrets. His research projects had taken him far into outer space and into the depths of the ocean. With his atomic earth blaster, Tom had probed under the earth's crust at the South Pole, and in other adventures he had faced danger in the jungles of Africa, New Guinea, and Yucatan. His latest achievement, receiving the visitor from Planet X, had been to construct a robot body for this mysterious brain energy from another world. Now, Tom realized, he was on the brink of another adventure which might hold unexpected dangers. Early the next morning the majestic _Sky Queen_ was hoisted from its underground hangar berth and hauled by tractor to its special runway. This mammoth, atomic-powered airplane had been Tom's first major invention. A three-deck craft, it was equipped with complete laboratory facilities for research in any corner of the globe. Jet lifters in the belly of the fuselage enabled the craft to take off vertically and also to hover. As Tom supervised the loading of the equipment, a foghorn voice boomed, "'Mornin', buckaroos!" The chunky figure of Chow Winkler came into view. Formerly a chuck-wagon cook in Texas, Chow was now head chef on Tom's expeditions. As usual, a ten-gallon hat was perched on his balding head and he was stomping along in high-heeled boots. "Wow! A shirt to end all shirts!" Tom chuckled. "Real high style, eh?" Chow twirled about to display his latest Western creation. The shirt seemed to be made of silvery fishlike scales, which glistened like a rainbow. "I figured as how this was just the thing fer an ocean jaunt," Chow added with a grin. "How soon do we take off, boss?" "As soon as we get the rest of this gear stowed," Tom replied. Twenty minutes later the _Sky Queen_ soared toward the ocean. Soon they came in sight of Fearing Island rocket base, a few miles off the coast. Once a barren stretch of sand dunes and scrub-grass, the island was now the Swifts' top-secret rocket laboratory, guarded by drone planes and radar. It served as the supply base for Tom's space station and as the launching area for all space flights. Seacopters and jetmarines were also berthed here. A radio call from Tom brought a sleek, strange-looking craft zooming up to join them. It was the _Sea Hound_, latest and largest model of Tom's amazing diving seacopter. It had an enclosed central rotor, powered by atomic turbines, with reversible-pitch blades for air lift or undersea diving. Superheated steam jets provided forward propulsion in either element.