"Let's hear it, Dad," Tom said eagerly. "I've been conducting some experiments with those space plants," the elder scientist said. "It looks as though they may prove to be a valuable nutritional source." The plants, Mr. Swift went on, showed promise of producing enormous amounts of protein quickly and cheaply--enough to increase the world's food supply by a sizable margin. Moreover, he had isolated a vitamin in this protein not found in any of man's present foods. "Doc Simpson has been working with me," Mr. Swift concluded. "He has been doing some experiments of his own with a vitamin extract from the space plants. He thinks it may prove highly beneficial to human beings." Tom was thrilled, and even Bud realized that Mr. Swift's cautious report could well turn out to be of history-making importance. "I'd say your news makes a phony space attack look pretty tame, Dad," Tom said, his eyes flashing enthusiastically. "With the earth's population increasing, this could be the answer to the food problem." "Don't tell Chow," Bud added, "or we may find spaceburgers on the next menu!" The Swifts chuckled. Chow's hobby of concocting weird dishes was a standing joke at Enterprises, and already had led to such dubious triumphs as armadillo stew and rattlesnake soup. Monday morning Tom buckled down seriously to the job of designing an undetectable sub. His drawing board was littered with sketches and diagrams when the phone rang, breaking in on his thoughts. Tom answered it with a scowl of impatience. The caller was Lester Morris. "Could you meet me at the yacht club to talk over the dance program?" Morris asked. Tom hesitated. For Sandy's and Phyl's sakes he was eager to do everything possible to make the square dance a success. But on the other hand.... "I'm pretty busy today," Tom said. "But my sister and my friend Bud Barclay can tell you what we want--probably better than I can. Suppose I ask them to meet you there after lunch?" There was a slight pause. "Very well," Morris agreed, although he sounded a bit annoyed. After hanging up, Tom phoned Bud and asked him to keep the appointment. Bud was only too happy to oblige, jumping at the chance to take Sandy out to lunch beforehand. At one o'clock the husky young pilot and his date strolled into the yacht club lounge. Lester Morris was nowhere in sight, so they sat down to wait. Twenty minutes later the musician still had not appeared. "I hope he hasn't forgotten," Sandy said, glancing at her wrist watch. "If he's a square-dance caller, his memory ought to be extra good," Bud joked. "Fine thing if he can't even remember the time of day!" After waiting a while longer, Bud decided to telephone Morris's home. But at that moment a thin, seedy-looking man came into the lounge. His close-set eyes and loudly striped suit combined to give him a somewhat disreputable appearance. "Good grief! Len Unger!" Sandy whispered. "What does he want with us?"