David had been waiting patiently for Dr. Henree and, in the meanwhile, enjoying the atmosphere of International City's newest restaurant. This was to be his first real celebration now that he had obtained Ms degree and qualified for full membership in the Council of Science.

He did not mind waiting. The Cafe Supreme still glistened from the freshly applied chromosilicone paints. The subdued light that spread evenly over the entire dining room had no visible source. At the wall end of David's table was the small, self-glowing cube which contained a tiny three-dimensional replica of the band whose music filled in a soft background. The leader's baton was a half-inch flash of motion and of course the table top itself was of the Sanito type, the ultimate in force-field modernity and, except for the deliberate flicker, quite invisible.

David's calm brown eyes swept the other tables, half-hidden in their alcoves, not out of boredom, but because people interested him more than any of the scientific gadgetry that the Cafe Supreme could gather. Tri-television and force-fields were wonders ten years before, yet were already accepted by all. People, on the other hand, did not change, but even now, ten thousand years after the pyramids were built and five thousand years after the first atom bomb had exploded, they were still the insoluble mystery and the unf aded wonder.

There was a young girl in a pretty gown laughing gently with the man who sat opposite her; a middle-aged man, in uncomfortable holiday clothing, punching the menu combination on the mechanical waiter while his wife and two children watched gravely; two businessmen talking animatedly over their dessert.

And it was as David's glance flicked over the businessmen that it happened. One of them, face congesting with blood, moved convulsively and attempted to rise. The other, crying out, stretched out an arm in a vague gesture of help, but the first had already collapsed in his seat and was beginning to slide under the table.

David had risen to his feet at the first sign of disturbance and now his long legs ate the distance between the tables in three quick strides. He was in the booth and, at a touch of his finger on the electronic contact near the tri-television cube, a violet curtain with fluorescent designs swept across the open end of the alcove. It would attract no attention. Many diners preferred to take advantage of that sort of privacy.

The sick man's companion only now found his voice. He said, "Manning is ill. It's some sort of seizure. Are you a doctor?"

David's voice was calm and level. It carried assurance. He said, "Now sit quietly and make no noise. We will have the manager here and what can be done will be done."

He had his hands on the sick man, lifting him as though he were a rag doll, although the man was heavyset. He pushed the table as far to one side as possible, his fingers separated uncannily by an inch of force-field as he gripped it. He laid the man on the seat, loosening the Magno-seams of his blouse, and began applying artificial respiration.

David had no illusion as to the possibility of recovery. He knew the symptoms: the sudden flushing, the loss of voice and breath, the few minutes' fight for life, and then, the end.

The curtain brushed aside. With admirable dispatch the manager had answered the emergency signal which David had tapped even before he had left his own table. The manager was a short, plump man, dressed in black, tightly fitting clothing of conservative cut. His face was disturbed.

"Did someone in this wing- " He seemed to shrink in upon himself as his eyes took in the sight.

The surviving diner was speaking with hysterical rapidity. "We were having dinner when my friend had this seizure. As for this other man, I don't know who he is."

David abandoned his futile attempts at revival. He brushed his thick brown hair off his forehead. He said, "You are the manager?"

"I am Oliver Gaspere, manager of the Cafe Supreme," said the plump man bewilderedly. "The emergency call from Table 87 sounds and when I come, it is empty. I am told a young man has just run into the booth of Table 94, and I follow and find this." He turned. "I shall call the house doctor."

David said, "One moment. There is no use in that This man is dead."

"What!" cried the other diner. He lunged forward, crying, "Manning!"

David Starr pulled him back, pinning him against the unseeable table top. "Easy, man. You cannot help him and this is no time for noise."

"No, no," Gaspere agreed rapidly. "We must not upset the other diners. But see here, sir, a doctor must still examine this poor man to decide the cause of death. I can allow no irregularities in my restaurant."

"I am sorry, Mr. Gaspere, but I forbid the examination of this man by anyone at the moment."

"What are you talking about? If this man dies of a heart attack..."

"Please. Let us have co-operation and not useless discussion. What is your name, sir?"

The living diner said dully, "Eugene Forester."

"Well, then, Mr. Forester, I want to know exactly what you and your companion ate just now."

"Sir!" The little manager stared at David, with eyes swelling out of their sockets. "Are you suggesting that something in the food caused this?"

"I'm not making suggestions. I'm asking questions."

"You have no right to ask questions. Who are you? You are nobody. I demand that a doctor examine this poor man."

"Mr. Gaspere, this is Council of Science business."

David bared the inner surface of his wrist, curling the flexible Metallite sleeve above it. For a moment it was merely exposed skin, and then an oval spot darkened and turned black. Within it little yellow grains of light danced and flickered in the familiar patterns of the Big Dipper and of Orion.

The manager's lips trembled. The Council of Science was not an official government agency, but its members were nearly above the government

He said, "I am sorry, sir."

"No apologies are necessary. Now, Mr. Forester, will you answer my first question?"

Forester muttered, "We had the special dinner number three."

"Both of you?"

"That's right."

David said, "Were there no substitutions on either part?" He had studied the menu at his own table. The Cafe Supreme featured extraterrestrial delicacies, but the special dinner number three was one of the more ordinary meals native to Earth: vegetable soup, veal chops, baked potato, peas, ice cream, and coffee.

"Yes, there was a substitution." Forester's brows drew together. "Manning ordered stewed marplums for dessert."

"And you didn't?''

"No."

"And where are the marplums now?" David had eaten them himself. They were plums grown in the vast Martian greenhouses, juicy and pitless, with a faint cinnamon flavor superimposed on their fruit-iness.

Forester said, "He ate them. What do you suppose?"

"How soon before he collapsed?"

"About five minutes, I think. We hadn't even finished our coffee." The man was turning sickly pale. "Were they poisoned?"

David did not answer. He turned to the manager, "What about the marplums?"

"There was nothing wrong with them. Nothing.'' Gaspere seized the curtains of the alcove and shook them in his passion, but did not forget to speak in the softest of whispers. "They were a fresh shipment from Mars, government tested and approved. We have served hundreds of portions in the last three nights alone. Nothing like this has happened till now."

"Just the same you had better give orders to eliminate marplums from the list of desserts until we can inspect them again. And now, in case it wasn't the marplums at all, please bring me a carton of some sort and we will transfer what is left of the dinner for study."

"Immediately. Immediately."

"And of course speak to no one of this."

The manager returned in a few moments, smearing his brow with a feathery handkerchief. He said, "I cannot understand it. I really cannot."

David stowed the used plastic dishes, with scraps of food still adhering to them, in the carton, added what was left of the toasted rolls, recapped the waxed cups in which the coffee had been served, and put them aside. Gaspere left off rubbing his hands frantically to reach a finger toward the contact at the edge of the table.

David's hand moved quickly, and the manager was startled to find his wrist imprisoned.

"But, sir, the crumbs!"

"I'll take those too." He used his penknife to collect each scrap, its sharp steel sliding easily along the nothingness of the force-field. David himself doubted the worth of force-field table tops. Their sheer transparency was anything but conducive to relaxation. The sight of dishes and cutlery resting on nothing could not help but leave diners tense, so that the field had to be put deliberately out of phase to induce continual interference sparkles that gave rise to an illusion of substance.

In restaurants they were popular since at the conclusion of a meal it was necessary only to extend the force-field a fraction of an inch to destroy whatever adhering crumbs and drops remained. It was only when David had concluded his collection that he allowed Gaspere to perform the extension, removing the safety catch first by a touch of the finger and then permitting Gaspere to use his special key. A new, absolutely clean surface was instantly presented.

"And now, just a moment." David glanced at the metal face of his wrist watch, then flicked a corner of the curtain aside.

He said softly, "Dr. Henree!"

The lanky middle-aged man who was sitting on what had been David's seat fifteen minutes earlier stiffened and looked about him with surprise.

David was smiling. "Here I am!" He put a linger to his lips.

Dr. Henree rose. His clothes hung loosely upon him and his thinning gray hair was combed carefully over a bald spot. He said, "My dear David, are you here already? I had thought you were late. But is anything wrong?"

David's smile had been short-lived. He said, "It's another one."

Dr. Henree stepped within the curtain, looked at the dead man, and muttered, "Dear me."

"That's one way of putting it," said David.

"I think," said Dr. Henree, removing his glasses and playing the mild force-beam of his pencil-cleaner over the lenses before replacing them, "I think we had better close down the restaurant."

Gaspere opened and closed his mouth soundlessly, like a fish. Finally he said in a strangled gasp, "Close the restaurant! It has been open only a week. It will be ruin. Absolute rum!"

"Oh, but only for an hour or so. We will have to remove the body and inspect your kitchens. Surely you want us to remove the stigma of food poisoning if we can, and surely it would be even less convenient for you to have us make arrangements for this in the presence of the diners."

"Very well then. I will see that the restaurant is made available to you, but I must have an hour's grace to allow present diners to finish their meals. I hope there will be no publicity."

"None, I assure you." Dr. Henree's lined face was a mask of worry. "David, will you call Council Hall and ask to speak to Conway? We have a procedure for such cases. He will know what to do."

"Must I stay?" put in Forester suddenly. "I feel sick."

"Who is this, David?" asked Dr. Henree.

"The dead man's dinner companion. His name is Forester."

"Oh. Then I am afraid, Mr. Forester, you will have to be sick here."

The restaurant was cold and repulsive in its emptiness. Silent operatives had come and gone. Efficiently they had gone through the kitchens atom by atom. Now only Dr. Henree and David Starr remained. They sat in an empty alcove. There were no lights, and the tri-televisions on each table were simply dead cubes of glass.

Dr. Henree shook his head. "We will learn nothing. I am sure of that from experience. I am sorry, David. This is not the proper celebration we had planned."

"Plenty of time for celebration later. You mentioned in your letters these cases of food poisoning, so I was prepared. Still, I wasn't aware of this intense secrecy which seems necessary. I might have been more discreet if I had known."

"No. It is no use. We cannot hide this trouble forever. Little by little there are tiny leaks. People see other people die while eating and then hear of still other cases. Always while they're eating. It is bad and will grow worse. Well, we will talk more of this tomorrow when you talk to Conway himself."

"Wait!" David looked deep into the older man's eyes. "There is something that worries you more than the death of a man or the death of a thousand. Something I don't know. What is it?"

Dr. Henree sighed. "I'm afraid, David, that Earth is in great danger. Most of the Council does not believe it and Conway is only half-convinced, but I am certain that this supposed food poisoning is a clever and brutal attempt at seizing control of Earth's economic life and government. And so far, David, there is no hint as to who is behind the threat and exactly how it is being accomplished. The Council of Science is entirely helpless!"