"That spine generates the plasma fields for the drive," his communicator was saying. There was no screen, but the voice was Cargill's. " We watched it during deceleration. That spiggot device beneath the spine probably feeds hydrogen into the fields."

"I'd better stay out of its way," said Mr. Whitbread.

"Right. The field intensity would probably wreck your instruments. It might affect your nervous systems too."

The alien ship was very close now. Whitbread fired bursts to slow himself. The attitude jets sounded like popcorn popping.

"See any signs of an air lock?"

"No, sir."

"Open your own air lock. Maybe that will get the idea across."

"Aye aye, sir." Whitbread could see the alien through the forward bubble. It was motionless, watching him, and it looked very like the photographs he had seen of the dead one in the probe. Jonathon Whitbread saw a neckless, lopsided head, smooth brown fur, a heavy left arm gripping something, two slender right arms moving frantically fast, doing things out of his field of vision.

Whitbread opened his air lock. And waited.

At least the Motie hadn't started shooting yet.

The Engineer was captivated. She hardly noticed the tiny vehicle nearby. There were no new principles embodied there. But the big ship!

It had a strange field around it, something the Engineer had never believed possible. It registered on half a dozen of the Engineer's instruments. To others the force envelope was partly transparent. The Engineer knew enough about the warship already to scare the wits out of Captain Blaine if he'd known. But it was not enough to satisfy an Engineer.

All that gadgetry! And metal!

The small vehicle's curved door was opening and closing now. It flashed lights on and off. Patterns of elect electromagnetic force radiated from both vehicles. The signals meant nothing to an Engineer.

It was the ship's gadetry that held her attention. The Field itself, its properties intriguing and puzzling, its underlying principles a matter of guesswork. The Engineer was ready to spend the rest of her life trying. For one look at the generator she would have died. The big ship's motive force was different from any fusion plant the Engineer had ever heard of; and its workings seemed to use the properties of that mysterious force envelope.

How to get aboard? How to get through that envelope? The intuition that came was rare for an Engineer. The small craft...was it trying to talk to her? It had come from the large craft. Then...

The small craft was a link to the larger ship, to the force envelope and its technology and the mystery of its sudden appearance.

She had forgotten danger. She had forgotten everything in the burning urge to know more about that field. The Engineer opened her air-lock door and waited to see what would happen.

"Mister Whitbread, your alien is trying to use probes on MacArthur," Captain Blaine was saying, "Commander Cargill says he has them blocked. If that makes the alien suspicious, it can't be helped. Has he tried any kind of probe on you?"

"No, sir."

Rod frowned and rubbed the bridge of his nose. "You're sure?"

"I've been watching the instruments, sir."

"That's funny. You're smaller, but you're close. You'd think he-"

"The air lock!" Whitbread snapped. "Sir, the Motie's opened his air lock."

"I see it. A mouth opened in the hull. Is that what you me an?"

"Yessir. Nothing coming out. I can see the whole cabin through that opening. The Motie's in his control cabin- permission to enter, sir?"

"Hmm. OK. Watch yourself. Stay in communication. And good luck; Whitbread."

Jonathon sat a moment, nerving himself. He had half hoped the Captain would forbid it as too dangerous. But of course midshipmen are expendable... Whitbread braced himself in the open air lock. The alien ship was very close. With the entire ship watching him, he launched himself into space.

Part of the alien's hull had stretched like skin, to open into a kind of funnel. A strange way to build an air lock, thought Whitbread. He used backpack jets to slow himself as he drifted straight into the funnel, straight toward the Motie, who stood waiting to receive him.

The alien wore only its soft brown fur and four thick pads of black hair, one in each armpit and one at the groin. "No sign of what's holding the air in, but there's got to be air in there," Whitbread told the mike. A moment later he knew. He had run into invisible honey.

The air lock closed against his back.

He almost panicked. Caught like a fly in amber, no forward, no retreat. He was in a cell 130 cm high, the height of the alien. It stood before him on the other side of the invisible wall, blank-faced, looking him over.

The Motie. It was shorter than the other, the dead one in the probe. Its color was different: there were no white markings through the brown fur. There was another, subtler, more elusive difference... perhaps the difference between the quick and the dead, perhaps something else.

The Motie was not frightening. Its smooth fur was like one of the Doberman pinschers Whitbread's mother used to raise, but there was nothing vicious or powerful looking about the alien. Whitbread would have liked to stroke its fur.

The face was no more than a sketch, without expression, except for a gentle upward curve of the lipless mouth, a sardonic half-smile. Small, fiat-footed, smooth-furred, almost featureless- It looks like a cartoon, Whitbread thought. How could he be afraid of a cartoon?

But Jonathon Whitbread was crouched in a space much too small for him, and the alien was doing nothing about it.

The cabin was a crowded patchwork of panels and dark crevasses, and tiny faces peered at him from the shadows.

Vermin! The ship was infested with vermin. Rats? Food supply? The Motie did not seem disturbed as one flashed into the open, then another, more dancing from cover to cover, crowding close to see the intruder.

They were big things. Much bigger than rats, much smaller than men. They peered from the corners, curious but timid. One dodged close and Whitbread got a good look. What he saw made him gasp. It was a tiny Motie!

It was a difficult time for the Engineer. The intruder's entry should have answered questions, but it only raised more.

What was it? Big, big-headed, symmetrical as an animal, but equipped with its own vehicle like an Engineer or a Master. There had never been a class like this. Would it obey or command? Could the hands be as clumsy as they looked? Mutation, monster, sport? What was it for?

Its mouth was moving now. It must be speaking into a communications device. That was no help. Even Messengers used language.

Engineers were not equipped to make such decisions; but one could always wait for more data.

Engineers had endless patience.

"There's air," Whitbread reported. He watched the telltales that showed in a mirror just above his eye level. "Did I mention that? I wouldn't want to try breathing it. Normal pressure, oxygen around 18 percent, CO2 about 2 percent, enough helium to register, and-"

"Helium? That's odd. Just how much?"

Whitbread switched over to a more sensitive scale and waited for the analyzer to work. "Around 1 percent. Just under."

"Anything else?"

"Poisons. SO2, carbon monoxide, nitrous oxides, ketones, alcohols, and some other stuff that doesn't read out with this suit. The light blinks yellow."

"Wouldn't kill you fast, then. You could breathe it a while and still get help in time to save your lungs."

"That's what I thought," Whitbread said uneasily. He began loosening the dogs holding down his faceplate.

"What does that mean, Whitbread?"

"Nothing, sir." Jonathon had been doubled over far too long. Every joint and muscle screamed for surcease. He had run out of things to describe in the alien cabin. And the thrice-damned Motie just stood there in its sandals and its faint smile, watching, watching...