"Good idea." As Admiral Walter extended a hand, his weather-beaten face softened. "And don't feel downhearted, son. You rate a Navy 'E' for the way you handled this operation. It would have succeeded if it hadn't been for that confounded enemy missile!" "Thank you, sir." Tom managed a grateful grin, in spite of his discouragement. Minutes later, the two boys embarked in a motor launch that took them to an aircraft carrier standing by in the vicinity. From the flattop they took off in a Navy jet for Shopton. Meanwhile, Mr. Swift remained aboard the _Recoverer_ to supervise the data processing. Tom, looking back from the soaring jet, could see one of the helicopters on its way to the missile ship to deliver the first batch of tapes. It was late afternoon when the Navy jet touched down on the Enterprises airfield. The Swifts' sprawling experimental station was a walled, four-mile-square enclosure with landing strips, work-shops, and laboratories, near the town of Shopton. Here Tom Jr. and his father developed their amazing inventions. Tom and Bud hopped into a jeep at the hangar and sped to the Administration Building, where Tom shared a double office with his father. Bud sank down into one of the deep-cushioned leather chairs, while Tom adjusted the Venetian blinds to let in the afternoon sunshine. The spacious office was furnished with twin modern desks, conference table, and drawing boards which swung out from wall slots at the press of a button. At one end of the room were the video screen and control board of the Swifts' private TV network. Here and there stood scale models of their inventions, a huge relief globe of the earth, and a replica of the planet Mars. "What are your plans for our search expedition, skipper?" Bud asked. Tom ran his fingers through his crew cut. "Let's see. We'd better take the _Sky Queen_, I think, and also--" Tom broke off as the desk intercom buzzed. Miss Trent, the Swifts' secretary, was on the wire. "Your father's calling over the radio, Tom." "Swell!" Tom flicked a switch to cut in the signal of his private telephone. "Hi, Dad! We just got back. Any news?" "Yes, son. We have the computer results," Mr. Swift replied. "Got a pencil handy?" Tom copied down the latitude and longitude figures as his father dictated. "According to the latest hydrographic maps, based on IGY findings," Mr. Swift went on, "this area is a high plateau of the Atlantic Ridge--it's near the St. Paul Rocks." "What about the depth?" "It averages between a hundred and three hundred feet," said the elder scientist. Tom gave a whistle. "Lucky break, eh?" "Maybe and maybe not," Mr. Swift said cautiously. "The bottom there is heavily silted." "Oh--oh." Tom made a wry face. "In that case, we may have some digging to do." "I'm afraid so. However, no use borrowing trouble." After a short discussion, the elder scientist added, "I'll probably fly home tomorrow, son. Give my love to Mother and Sandy."