Conquering outer space, probing the ocean's secrets, drilling to the earth's core--these were only a few of Tom Swift's many exciting exploits. In his first adventure, Tom, in his Flying Lab, had gone to South America to fend off a gang of rebels seeking a valuable radioactive ore deposit. In his most recent challenge, Tom had defied the threats of Oriental killers determined to ferret out the secret of the Swifts' latest space research. As the two boys silently recalled the exciting events of the past months, Mr. Swift returned to the living room. Tom and Bud leaned forward in their chairs. "Well, boys," Mr. Swift said, "as I started to tell you, the space receiver picked up a message today from our unknown planetary friends. The message informed us that they are sending a visitor to earth--a visitor consisting of _pure energy!_" "_Energy?_" Tom was startled. "I don't get it, Dad!" "Frankly, I don't quite understand it myself," Tom Sr. confessed. "The message didn't explain how or in what form the energy would arrive. But, at any rate, they want us to construct some sort of container for it." The elder scientist paused thoughtfully. "In my opinion, the energy which they speak of must be a sort of invisible brain. The symbols were rather difficult to decode, but apparently our job will be to construct a device through which the energy will be able to receive impressions of what life is like here on earth, and also to communicate its own responses to us." Tom sat bolt upright. "Dad, this is terrific news!" he exclaimed. "If we're able to make this energy or 'brain' communicate, it may be able to tell _us_ what the space people are like!" Mr. Swift nodded, his own eyes blazing with as much excitement as Tom's were. Bud, too, was deeply impressed but could not resist quipping, "What sort of body will you give it? How about a beautiful, superintelligent space girl for me to date?" "Nothing doing!" Sandy retorted mischievously. "I insist on a handsome young man who'd have time to take two nice earth girls out on dates!" "Ouch!" Bud pretended to wince. "I really left myself wide open for that one!" Mrs. Swift put in, "Goodness, mightn't it get out of control and be rather overpowering? Suppose it went berserk!" "Rather an unpleasant possibility," Mr. Swift agreed, smiling wryly. "But I trust our space friends wouldn't let that happen." Both he and Tom became thoughtful as they discussed the problem. "The energy will arrive in two weeks," Mr. Swift added. "Unfortunately that phone call was a request that I go to Washington on urgent government business. So you may have to take over and work out a solution on your own, Tom." It was a sobering thought to the young inventor. "You were right, Mother. This is a terrific challenge." Soon afterward, the little gathering broke up. Bud, who had left his own convertible at the Swifts' that morning, offered to drop Phyl at her home.