Calhoun glanced at Murgatroyd and said dryly, "I've reason to be pleased myself. How about Doctor Kelo and his friends?"
"We'll get him! He can't get off the planet, and we'll find him! There's only one ship aground at the spaceport; it came in two days ago. It's stayed in port under self-quarantine at our request. We've instructed it not to take anyone aboard. We're chartering it to go to other planets and buy foodstuffs to replace the ones we're testing and destroying."
Calhoun, stroking Murgatroyd, said more dryly than before, "I wouldn't. You'd have to send currency to pay for the stuff you want to import. On two previous occasions very, very large sums gathered for that purpose have disappeared. I'm no policeman but that could be the reason for the plague. There are some people who might start a plague for the express purpose of being entrusted with some scores of millions of credits . . ."
There was silence at the other end of the conversation. Then a man's voice, raging, "If that's it!"
Calhoun broke in.
"In my orbit I'll be below your horizon in minutes. I'll call back. My orbit's very close to two hours duration."
"If that's it," repeated the voice, raging, "We'll . . ."
There was silence. Calhoun said very cheerfully, "Murgatroyd, I'm good at guessing the way a relatively honest man's mind works. If I'd told them earlier that the plague victims were murdered, they'd have discounted the rest of what I had to say. But I'm learning the way a criminal's mind works too! It takes a criminal to think of burning down a house to cover up the fact that he robbed it. It takes a criminal to think of killing a man for what he may carry in his pockets. It would take a criminal to start a plague so he can gather money to steal, under the pretense that he's going to use it to buy unpoisoned food to replace the food he's poisoned. I had trouble understanding that!"
Murgatroyd said, "Chee!"
He got up. He walked in a rather wobbly fashion as if testing his strength. He came back and nestled against Calhoun. Calhoun petted him. Murgatroyd yawned. He'd been weakened by his illness. He still didn't understand it. Tormals are not accustomed to being ill.
"Now," said Calhoun reflectively, "I make a guess at how certain criminal minds will work if they eavesdropped just then. We've spoiled their crime on Kryder II. They'd put a lot of time and trouble into committing it. Now they've had their trouble and committed their murders for nothing. I think, I think they'll be angry. With me."
He settled Murgatroyd comfortably. He went about the ship stowing things away. The samples of ditch water and of foodstuffs he placed so no shock or sudden acceleration could spill them. He made sure there were no loose objects about the control-room. He went down below and made especially sure that the extra plastic-sealed control-central unit was properly stowed, and that the spacesuit worn by one of the two men to board the Med Ship at breakout was suitably held fast. They'd be turned over to the laboratories at headquarters. If carefully disassembled the control-central unit would give positive proof that a certain man in the headquarters technical staff had installed it. Suitable measures would be taken. The spacesuit would identify the man now at the bottom of a rocky crevasse on an icy, uninhabited world.
By the time Calhoun's preparations were finished, the ship had nearly completed its orbital round. Calhoun put Murgatroyd in his cubbyhole. He fastened the door so the little animal couldn't be thrown out. He went to the pilot's chair and strapped in.
Presently he called, "Med Ship Aesclipus Twenty calling ground! Med Ship calling ground!"
An enraged voice answered immediately.
"Ground to Med Ship! You were right! The ship in the spaceport lifted off on emergency rockets before we could stop it! It must have listened in when you talked to us before! It got below the horizon before we could lock on!"
"Ah!" said Calhoun comfortably. "And did Doctor Kelo get aboard?"
"He did!" raged the voice. "He did! It's inexcusable! It's unbelievable! He did get aboard and we moved to seize the ship and its rockets flamed and it got away!"
"Ah!" said Calhoun, again comfortably. "Then give me coordinates for landing."
He had them repeated. Of course, if someone were eavesdropping . . . but he shifted the Med Ship's orbit to bring him to rendezvous at a certain spot at a certain time, a certain very considerable distance out from the planet.
"Now," he said to Murgatroyd, "we'll see if I understand the psychology of the criminal classes, in fact . . ."
Then he remembered that Murgatroyd was locked in his cubbyhole. He shrugged. He sat very alertly in the pilot's chair while the planet Kryder II revolved beneath him.
There was silence except for those minute noises a ship has to make to keep from seeming like the inside of a tomb. Murmurings. Musical notes. The sound of traffic. All very faint but infinitely companionable.
The needle of the nearest-object dial stirred from where it had indicated the distance to the planet's surface. Something else was nearer. It continued to approach. Calhoun found it and swung the Med Ship to face it, but he waited. Presently, he saw an infinitesimal sliver of reflected sunlight against the background of distant stars. He mentally balanced this fact against that, this possibility against that.
He flicked on the electron telescope. Yes. There were minute objects following the other ship. More of them appeared, and still more. They were left behind by the other ship's acceleration, but they spread out like a cone of tiny, deadly, murderous missiles. They were. If any one crashed into the Med Ship it could go clear through from end to end.
This was obviously the ship that had placed a man aboard the Med Ship to impersonate Calhoun aground. It was the ship whose company was ultimately responsible for the plague on Kryder II, and before that on Castor IV, and for another before that. It had been aground to receive, at a suitable moment, very many millions of credits in currency to pay for unpoisoned foodstuffs for Kryder II. Through Calhoun, it had had all its trouble for nothing. It came to destroy the Med Ship as merited if inadequate punishment.
However, Calhoun found himself beautifully confident in his own competence. He was headed, of course, for a ship that meant to destroy him. It tossed out missiles to accomplish that purpose. Dropping behind as they did, the effect was of the other ship towing a cone-shaped net of destruction.
So Calhoun jammed down his rocket-controls to maximum acceleration and plunged toward it. It was a ship guided by criminals, with criminal psychology. They couldn't understand and at first couldn't believe that Calhoun—who should be their victim—would think of anything but attempts to escape. But presently it was borne upon them that he seemed to intend to ram them in mid-space.
The other ship swerved. Calhoun changed course to match. The other ship wavered. Its pilot couldn't understand. He'd lost the initiative. The Med Ship plunged for the very nose of the other vessel. They moved toward each other with vastly more than the speed of rifle bullets. At the last instant the other ship tried crazily to sheer off. At that precise moment Calhoun swung the Med Ship into a quarter-turn. He cut his rockets and the Aesclipus Twenty plunged ahead, moving sidewise, and then Calhoun cut in his rockets again. Their white-hot flames, flittering through a quarter-mile of space, splashed upon the other ship. They penetrated. They sliced the other ship into two ragged and uneven halves, and those two halves wallowed onward.