Chapter I

The first thing McCracken did was shoot a Mercurian native. But then McCracken, although he had powerful muscles, was never supposed to be very strong in the head.

The expedition was in the Twilight Zone, naturally, at the time. Without special clothing, which no one had, both the perpetual night of the Cold Side and the furnace heat of the Hot Side were out of the question. The Twilight Zone at this point was about forty miles wide, and the _Astrolight_ had been skillfully brought down smack in the middle of it. Two hours after the landing, having ascertained that the air was as breathable as Kalinoff had reported, McCracken went out and aimed his explosive bullet at the Mercurian.

If it hadn't been for Carvalho, who accompanied him, the rest of the group would have known nothing of the incident. It was Carvalho who reported what had happened to Lamoureux, captain of the expedition.

McCracken, of course, burst into vigorous denials that he had shot a native. "You don't think I'd be fool enough to go around looking for trouble, do you?"

* * * * *

Lamoureux thought he would, but didn't say so. "You did shoot at something. We heard the report."

"I tried to hit a dangerous bird."

"What sort of bird was it?"

"Kind of like a penguin, I'd say, but with a broader face. No bill to speak of--"

"Then don't speak of it," snapped Lamoureux. "Did you score a hit?"

"I think the explosion caught it in the shoulder. It got away."

"Thank God for small favors," said Lamoureux. "That bird, you pigeon-brain, was a Mercurian. How do you expect intelligent inhabitants of other planets to look? Like you? They'd die of mortification."

"Damn it, how was I to know?"

"I told you not to shoot unless you were attacked." Lamoureux scowled. "Kalinoff is somewhere in the Twilight Zone and we were supposed to find him with the help of the Mercurians. It may interest you to know that, while you were out at target practice, some of them came around here and began to behave as if they wanted to be friendly. Then they suddenly disappeared. I imagine they got news of what you had done. A fat lot of help they'll give us now."

"We'll run across Kalinoff without them," said McCracken confidently.

Carvalho, who had a habit of looking for the dark side of every situation, and finding it, suggested, "Suppose the Mercurians attack us?"

McCracken said, "They haven't any weapons."

"How do you know?"

"Kalinoff didn't mention any."

Lamoureux emitted a laugh that sounded like an angry bark. "Kalinoff wouldn't know. _He_ was friendly with them. He did report that they were an intelligent race. It'll be too bad if they use their intelligence against us."

McCracken thrust out his jaw. There was a streak of stubbornness in him, and he was not going to take too many dirty cracks lying down. He growled, "I think you're making a mountain out of an anthill."

"Molehill," corrected Lamoureux.

"Whatever it is. What if Kalinoff did say the Mercurians would help us? You can't take his word for it. Everybody knows what Kalinoff is."

Lamoureux frowned. "Kalinoff is a great man and a great explorer."

"They call him the interplanetary screwball."

"Not on this expedition, they don't, McCracken. You will please keep a civil tongue in your head."

"There's nothing wrong in what I'm saying. Kalinoff _is_ a screwball, and you know it, Captain. He's always playing practical jokes. Look at how he got that Martian senator into the same cage with a moon-snake, and locked the door on him. The senator had a fit. How was he to know the snake was harmless?"

"You don't think Kalinoff would play jokes when his own life was at stake, do you?"

"Once a screwball," insisted McCracken firmly, "always a screwball."

Lamoureux lost patience. "Once an idiot, always an idiot. Get over to the ship and help with the unpacking. And remember, if we don't find Kalinoff, it'll be your fault, and God help you."

* * * * *

Having, he hoped, left McCracken feeling properly ashamed of himself, Lamoureux walked away. The responsibility was beginning to weigh him down. The other nineteen men in the expedition thought they were merely trying to rescue an intrepid explorer for the sake of human life, which was supposed to be sacred. They didn't know that, behind his screwball surface, Kalinoff was as shrewd as they came. He had made some valuable discoveries--and promptly staked out a claim to them.

He had run across large quantities of stable isotopes of metals whose atomic numbers ranged from 95 to 110. These had remarkable and useful properties.

They were, to begin with, of unusual value as catalysts in chemical reactions. For example, element 99, in the presence of air, was a more powerful oxidizing agent than platinum or palladium was a reducing agent, in the presence of hydrogen. And the oxidations could be controlled beautifully, could be made to affect almost any part of a complicated organic molecule at a time. Element 99 was recoverable, and could be used again and again. A few hundred grams of it alone might very well pay for the cost of the entire expedition.

Add the value of a few kilos of elements 101 to 110, and Kalinoff had discovered enough to make him and a few other people rich for life.

Lamoureux wanted to be one of those other people. He had three kids he wanted to send through Lunar Tech; he had a wife with expensive tastes in robot servants; and he had relatives. Let him get Kalinoff off this God-forsaken planet, where he had been marooned for the past year, and even an interplanetary screwball might be expected to show some feeling of gratitude. Combine this feeling of gratitude with a reasonably fair contract already printed, and needing only the explorer's scrawl to give it validity, and Lamoureux could almost feel the money in his pocket. If only McCracken had not spoiled everything by his stupidity--

Lamoureux shuddered to think that by the time they got to him Kalinoff might be dead, and they would have to do business with his heirs--heirs who had no sense of gratitude to impair their business judgment. He felt suddenly poor again. But he put the gloomy thought out of his head, and went on with his work.

* * * * *

Unpacking would be finished in a couple of hours at most. Meanwhile there was some preliminary exploring to be done. The neighboring ground must be surveyed, and landmarks noted, so that they would have a suitable base from which to start their search. Kalinoff had talked about two mountains with a saddlelike ridge joining them. Those two mountains shouldn't be too difficult to recognize--if ever the expedition ran across them.

McCracken, obeying orders, was lending a hand at the unloading. What with Mercury's low gravity, and his own strength, he had no difficulty in wrestling around the five hundred pound crates in which their supplies had been packed. However, he was of little help in getting the work done. With what Lamoureux decided was characteristic stupidity, he seemed to be mostly in everyone else's way.

Lamoureux called, "McCracken!"

"Yes, sir."

"Let go those crates. The others will handle them. I want you--"

Lamoureux stopped suddenly. A distant sound had come to his ears--the explosion of a bullet.

There was a sudden silence that was so absolute, Lamoureux could hear his men breathe. Another bullet exploded, then another--and silence again.

Somebody whispered, "The natives don't have guns. It must be Kalinoff!"

"What luck to find him this way!"

Lamoureux had run for his own gun. He fired ten shots into the air and waited. But there was no reply.

Lamoureux spat out his orders with machine-gun speed. "McCracken, you, Carvalho, and Haggard set out to the right. The shots seemed to be coming from that direction. But we'll take no chances. Gronski, Terrill and Cannoni, go straight ahead. Marsden and Blaine, to the left; Robinson and Sprott, to the rear. Spread out fast and keep your eyes peeled. Don't go any further away than the sound of a bullet. Uncover every damned white-bush, and tear up every desert-cat hill, but don't come back without Kalinoff. Now get going!"

* * * * *

The men started on a run. Lamoureux, waiting impatiently, walked up and down in growing excitement. He had come prepared for a three months' search, expected it. He had pictured himself and his men, exhausted by a long trek across the planet, coming upon the startled Kalinoff, striking a magnificent attitude, and saying, with characteristic Tellurian modesty, "Dr. Livingston, I presume." And, instead, he was going to find Kalinoff in less than a day. He ran into the ship, got out the printed contract, and read it hastily.

All was in order. He'd have Kalinoff's signature that day.

A half hour passed, and Lamoureux fired ten more shots. Haskell, the cook, was looking at the sky with a troubled expression on his face. He approached Lamoureux apologetically. "Say, Captain--"

"What is it, Haskell?"

"Does it ever rain on Mercury?"

"Never. No rain, no snow, no hail. No man who has ever set foot on the planet has come across any sort of bad weather. Kalinoff emphasizes that fact."

"Well, that's what I seemed to remember. But just now I thought I felt a drop of rain."

"Impossible, Haskell. Some bird--"

Lamoureux stopped abruptly. He, too, had thought he felt a drop of rain.

Haskell held out a hairy paw. "I thought I felt another one." His eyes fell on the brown rocks. "Say, here's a big drop that splashed."

The brown rocks were being slowly spotted with black. And, as Lamoureux stared, he felt his head grow wet. There was no doubt about it. It was raining.

His mouth dropped open. "But it doesn't rain on Mercury!"

The sky was a dull gray now, and the patter of rain drowned out his words. He realized suddenly that he was becoming soaked.

Haskell was running for the ship. Lamoureux followed him and slammed the door shut. The men who had not been sent to search for Kalinoff were already inside. The rain rattled on the hull of the _Astrolight_, and on the parched ground.

Lamoureux stared through the side port and repeated blankly, "But it doesn't rain on Mercury!"

Fortunately, the noise of the rain was so loud that no one heard him say it.