“Omnivores?” The man seated next to Captain Kondo was tall and thin-boned, as though he had already lived all his life in a low-gee setting. “What are they, some kind of pet animals?”

The captain — short, serious, and very dignified — looked at his neighbor in horror. “Pets, sir? Not in space, sir. I know that back on Earth in the old days the sailors carried goats and guinea pigs and turtles for fresh meat, but we are prohibited. No pets allowed, orders of the Outer Systems Line. Mr. Marr and the engineer are overhauling the Diabelli Omnivores — our main engines, that keep pushing us along so comfortably. If you sit quiet and remain still, you will hear and feel them.”

Jan already had. Lying in her bunk the first two nights out, she had detected a faint vibration.

“But if you do feel them,” Captain Kondo went on, “it means that they are not at maximum efficiency. A perfectly efficient engine would make no noise at all, and would not vibrate. That’s what the crew are working on now. Before we get to Mars, all that work has to be over and done with. Then you will have the first officer here at dinner, and less of my dull company.”

He said it with a smile, as though he didn’t believe that anyone might possibly find him boring; but Jan had the feeling that he was looking at her particularly when he mentioned the first officer.

On the seventh day, the OSL Achilles was nearing Mars orbit rendezvous when a knock came on the door of Jan’s cramped little stateroom, far forward near the bows of the ship.

She was curled up on the bed dressed only in briefs and a tank top, but expecting it could only be Sebastian she called, “It’s open. Come in.”

Paul Marr entered, wearing a smile that vanished instantly when he guessed from her clothing that she had been expecting someone else. “I’m sorry. I should have said who I was.”

“It’s all right.” Jan pulled a bed-cover over her bare legs. “My fault. I thought it was Sebastian, and we’re pretty informal with each other. You get that way if you took baths together when you were kids.”

She noticed something odd about his appearance. He was dressed in a newly-pressed white uniform, but his hands were dirty and his nails grimy, as though no amount of scrubbing could get them clean. She went on, “I would ask you to sit down, but there’s not room in here to swing a cat.”

“No pets allowed. Orders of the Outer System Line.” He didn’t smile when he said it, but Jan felt certain that he had been told about her dinner two nights earlier with Captain Kondo. Her conviction was confirmed when he said, “We finished work on the Omnivores just a couple of hours ago.

They’re as clean and beautiful and efficient now as they ever will be. I wondered if you’d like to go aft with me and take a look at them before we power down and settle into Mars orbit.”

“Dressed like this?”

“Dressed any way you like.” He hesitated, then added, “You look pretty good to me. But I’ll wait outside.”

Which left Jan with a small problem. She wanted to be at her best, but she had brought with her exactly one stylish dress. She had been holding it in reserve, waiting for a night when Paul Marr finally appeared for dinner. She didn’t want to waste it on a tour of the ship’s engine room, and anyway it didn’t feel right for that. Engines, if they were anything like the methane power drives on the Global Minerals’ platform, made you dirty if you so much as glanced at them.

She scanned her minimal wardrobe and settled for a dark green top and cut-offs, with flat-heeled pumps. At their first meeting she had noticed that Paul Marr was no taller than she was. She didn’t care, and hoped that he didn’t. You would think that by now no one would worry about a woman’s height, but she knew for a fact that some men did, just as they worried about age differences. She suspected that Paul was at least five years younger than she was.

At the last moment she changed into high-heeled open-toed sandals. If he had old-fashioned hang-ups on height or age, she might as well find out about them now.

He was leaning against the wall of the narrow corridor when she emerged. His scan of her, from toes to head — five centimeters taller than him — produced a delighted smile. “So far as I was concerned,” he said, “you could have gone as you were. But I must say you look better now. In fact, you look just terrific.”

So did he. Jan wondered what she might be getting herself into. The strange feeling of exhilaration had not left her. To depart Earth was to enter a zone of space and time where anything was possible.

He didn’t take her arm, nor did she expect him to. This was a member of the crew, suitably polite and formal with a passenger. But he did walk very close, guiding her along the spiraling corridor that wound its way aft. Since the ship was decelerating into Mars orbit, the way aft was all “downhill.”

At the rear bulkhead they paused. Jan pointed to the sign.

Paul shrugged. “You wouldn’t want it to welcome just anybody, when the ship’s control room is back here. The sign ought to add, ‘Unless accompanied by a ship’s officer.’ That’s me.” He slid the hatch open and waved her through.

Since the area also contained the living quarters of crew members, who spent far more time aboard than any passenger, Jan expected the rooms to be bigger and better furnished than her own cramped area. Just the opposite seemed to be the case. Rather than the bright blues and yellows she had become accustomed to, the walls aft were painted in dingy khaki and a hideous lurid green. The passages were even narrower than the spiral that had brought them here, more like tunnels for rats than corridors for human beings.

“A couple of reasons for that,” Paul said in answer to her question. “First, the crew are at home in any acceleration from free-fall to two-gees — that’s emergency only, by the way. We’re used to wriggling our way along, and wider corridors wouldn’t make that any easier. Also, you are seeing the worst part, the way back to the engines. The captain’s quarters are big and pretty plushy, off to the left. Mine don’t match up to his, but they’re comfortable. Maybe you’d like to take a look at them sometime.”

That sounded like another hint, and not a particularly subtle one. Jan glanced at Paul Marr, but his eyes stated straight ahead as he added, “Not today, though, we don’t have enough time.”

Enough time for what? His expression remained serious, and that was fine. The last thing she wanted was a leer or a sly wink.

They had reached the hatch leading down to the engine room. Paul said, “Don’t touch anything unless I tell you that it’s all right,” and slid through onto a tight spiral staircase of open metal rungs.

Jan followed him down, glad that she had chosen cut-offs but with second thoughts about the heels on her sandals. She didn’t know what she had expected to find — flaming rockets, or a ball of nuclear fire? — but the reality was not impressive. The engine room contained no people, and no furnishings of any kind. She and Paul Marr stood on a small flat platform, less than two meters across, in the middle of the room. On each side, arranged in a hexagon and within touching distance, stood six upright bulbous blue cylinders.

“Here we are,” said Paul. “The famous Diabelli Omnivores. Fusion drives that have transformed travel around the whole system.”

“Those things?” Jan asked.

“These things.” Paul patted one of the blue cylinders. “I’m sorry if you’re not impressed.”

“Maybe if they were working I would be.” And then Jan realized her error. Since the ship was decelerating, the drive must be on, and these engines had to be working.

Instead of replying, Paul took her wrist in his hand. His fingers were soft and smooth, not like someone who had spent the past week fiddling with engines. He moved her hand until it lay palm-down on the surface of one of the blue cylinders. “Feel anything?”