It was chromazone again. Muller had kept most of the gang from coming back to hydroponics, but he, Jenny, Pietro, Wilcox and myself were enough to fill the room with the smell of sick fear. Now less than half of the original space was filled with healthy plants. Some of the tanks held plants already dead, and others were dying as we watched; once beyond a certain stage, the stuff acted almost instantly—for hours there was only a slight indication of something wrong, and then suddenly there were the dead, bleached plants.

Wilcox was the first to speak. He still looked like some nattily dressed hero of a space serial, but his first words were ones that could never have gone out on a public broadcast. Then he shrugged. "They must have been poisoned while we were all huddled over Sam's body. Who wasn't with us?"

"Nonsense," Pietro denied. "This was done at least eighteen hours ago, maybe more. We'd have to find who was around then."

"Twenty hours, or as little as twelve," Jenny amended. "It depends on the amount of the dosage, to some extent. And...." She almost managed to blush. "Well, there have been a lot of people around. I can't even remember. Mr. Grundy and one of the men, Mr. Wilcox, Dr. Napier—oh, I don't know!"

Muller shook his head in heavy agreement. "Naturally. We had a lot of work to do here. After word got around about Hendrix, we didn't try to conceal much. It might have happened when someone else was watching, too. The important thing, gentlemen, is that now we don't have reserve enough to carry us to Saturn. The plants remaining can't handle the air for all of us. And while we ship some reserve oxygen...."

He let it die in a distasteful shrug. "At least this settles one thing. We have no choice now but to return to Earth!"

"Captain Muller," Pietro bristled quickly, "that's getting to be a monomania with you. I agree we are in grave danger. I don't relish the prospect of dying any more than you do—perhaps less, in view of certain peculiarities! But it's now further back to Earth than it is to Saturn. And before we can reach either, we'll have new plants—or we'll be dead!"

"Some of us will be dead, Dr. Pietro," Wilcox amended it. "There are enough plants left to keep some of us breathing indefinitely."

Pietro nodded. "And I suppose, in our captain's mind, that means the personnel of the ship can survive. Captain Muller, I must regard your constant attempt to return to Earth as highly suspicious in view of this recurrent sabotage of the expedition. Someone here is apparently either a complete madman or so determined to get back that he'll resort to anything to accomplish his end. And you have been harping on returning over and over again!"

Muller bristled, and big heavy fist tightened. Then he drew himself up to his full dumpy height. "Dr. Pietro," he said stiffly, "I am as responsible to my duties as any man here—and my duties involve protecting the life of every man and woman on board; if you wish to return, I shall be most happy to submit this to a formal board of inquiry. I—"

"Just a minute," I told them. "You two are forgetting that we've got a problem here. Damn it, I'm sick of this fighting among ourselves. We're a bunch of men in a jam, not two camps at war now. I can't see any reason why Captain Muller would want to return that badly."

Muller nodded slightly. "Thank you, Mr. Tremaine. However, for the record, and to save you trouble investigating there is a good reason. My company is now building a super-liner; if I were to return within the next six months, they'd promote me to captain of that ship—a considerable promotion, too."

For a moment, his honesty seemed to soften Pietro. The scientist mumbled some sort of apology, and turned to the plants. But it bothered me; if Muller had pulled something, the smartest thing he could have done would be to have said just what he did.

Besides, knowing that Pietro's injunction had robbed him of a chance like that was enough to rankle in any man's guts and make him work up something pretty close to insanity. I marked it down in my mental files for the investigation I was supposed to make, but let it go for the moment.

Muller stood for a minute longer, thinking darkly about the whole situation. Then he moved toward the entrance to hydroponics and pulled out the ship speaker mike. "All hands and passengers will assemble in hydroponics within five minutes," he announced. He swung toward Pietro. "With your permission, Doctor," he said caustically.

The company assembled later looked as sick as the plants. This time, Muller was hiding nothing. He outlined the situation fully; maybe he shaded it a bit to throw suspicion on our group, but in no way we could pin down. Finally he stated flatly that the situation meant almost certain death for at least some of those aboard.

"From now on, there'll be a watch kept. This is closed to everyone except myself, Dr. Pietro, Mr. Peters, and Dr. Jenny Sanderson. At least one of us will be here at all times, equipped with gas guns. Anyone else is to be killed on setting foot inside this door!" He swung his eyes over the group. "Any objections?"

---

Grundy stirred uncomfortably. "I don't go for them science guys up here. Takes a crazy man to do a thing like this, and everybody knows...."

Eve Nolan laughed roughly. "Everybody knows you've been swearing you won't go the whole way, Grundy. These jungle tactics should be right up your alley."

"That's enough," Muller cut through the beginnings of the hassle. "I trust those I appointed—at least more than I do the rest of you. The question now is whether to return to Earth at once or to go on to Saturn. We can't radio for help for months yet. We're not equipped with sharp beams, we're low powered, and we're off the lanes where Earth's pick-ups hunt. Dr. Pietro wants to go on, since we can't get back within our period of safety; I favor returning, since there is no proof that this danger will end with this outrage. We've agreed to let the result of a vote determine it."

Wilcox stuck up a casual hand, and Muller nodded to him. He grinned amiably at all of us. "There's a third possibility, Captain. We can reach Jupiter in about three months, if we turn now. It's offside, but closer than anything else. From there, on a fast liner, we can be back on Earth in another ten days."

Muller calculated, while Peters came up to discuss it. Then he nodded. "Saturn or Jupiter, then. I'm not voting, of course. Bullard is disqualified to vote by previous acts." He drew a low moan from the sick figure of Bullard for that, but no protest. Then he nodded. "All those in favor of Jupiter, your right hands please!"

I counted them, wondering why my own hand was still down. It made some sort of sense to turn aside now. But none of our group was voting—and all the others had their hands up, except for Dr. Napier. "Seven," Muller announced. "Those in favor of Saturn."

Again, Napier didn't vote. I hesitated, then put my hand up. It was crazy, and Pietro was a fool to insist. But I knew that he'd never get another chance if this failed, and....

"Eight," Muller counted. He sighed, then straightened. "Very well, we go on. Dr. Pietro, you will have my full support from now on. In return, I'll expect every bit of help in meeting this emergency. Mr. Tremaine was correct; we cannot remain camps at war."

Pietro's goatee bobbed quickly, and his hand went out. But while most of the scientists were nodding with him, I caught the dark scowl of Grundy, and heard the mutters from the deckhands and the engine men. If Muller could get them to cooperate, he was a genius.

Pietro faced us, and his face was serious again. "We can hasten the seeding of the plants a little, I think, by temperature and light-and-dark cycle manipulations. Unfortunately, these aren't sea-algae plants, or we'd be in comparatively little trouble. That was my fault in not converting. We can, however, step up their efficiency a bit. And I'm sure we can find some way to remove the carbon dioxide from the air."

"How about oxygen to breathe?" Peters asked.

"That's the problem," Pietro admitted. "I was wondering about electrolyzing water."

Wilcox bobbed up quickly. "Can you do it on AC current?"

Lomax shook his head. "It takes DC."

"Then that's out. We run on 220 AC. And while I can rectify a few watts, it wouldn't be enough to help. No welders except monatomic hydrogen torches, even."

Pietro looked sicker than before. He'd obviously been counting on that. But he turned to Bullard. "How about seeds? We had a crop of tomatoes a month ago—and from the few I had, they're all seed. Are any left?"

Bullard rocked from side to side, moaning. "Dead. We're all gonna be dead. I told him, I did, you take me out there, I'll never get back. I'm a good man, I am. I wasn't never meant to die way out here. I—I—"

He gulped and suddenly screamed. He went through the door at an awkward shuffle, heading for his galley. Muller shook his head, and turned toward me. "Check up, will you, Mr. Tremaine? And I suggest that you and Mr. Peters start your investigation at once. I understand that chromazone would require so little hiding space that there's no use searching for it. But if you can find any evidence, report it at once."

Peters and I left. I found the galley empty. Apparently Bullard had gone to lie on his stomach in his bunk and nurse his terror. I found the freezer compartments, though—and the tomatoes. There must have been a bushel of them, but Bullard had followed his own peculiar tastes. From the food he served, he couldn't stand fresh vegetables; and he'd cooked the tomatoes down thoroughly and run them through the dehydrator before packing them away!

---

It was a cheerful supper, that one! Bullard had half-recovered and his fear was driving him to try to be nice to us. The selection was good, beyond the inevitable baked beans; but he wasn't exactly a chef at best, and his best was far behind him. Muller had brought Wilcox, Napier and Peters down to our mess with himself, to consolidate forces, and it seemed that he was serious about cooperating. But it was a little late for that.

Overhead, the fans had been stepped up to counteract the effect of staleness our minds supplied. But the whine of the motors kept reminding us our days were counted. Only Jenny was normal; she sat between Muller and Pietro, where she could watch my face and that of Napier. And even her giggles had a forced sound.

There were all kinds of things we could do—in theory. But we didn't have that kind of equipment. The plain fact was that the plants were going to lose the battle against our lungs. The carbon dioxide would increase, speeding up our breathing, and making us all seem to suffocate. The oxygen would grow thinner and thinner, once our supplies of bottled gas ran out. And eventually, the air wouldn't support life.

"It's sticky and hot," Jenny complained, suddenly.

"I stepped up the humidity and temperature controls," I told her. She nodded in quick comprehension, but I went on for Muller's benefit. "Trying to give the plants the best growing atmosphere. We'll feel just as hot and sticky when the carbon dioxide goes up, anyhow."

"It must already be up," Wilcox said. "My two canaries are breathing faster."

"Canaries," Muller said. He frowned, though he must have known of them. It was traditional to keep them in the engine-room, though the reason behind it had long since been lost. "Better kill them, Mr. Wilcox."

Wilcox jerked, and his face paled a bit. Then he nodded. "Yes, sir!"

That was when I got scared. The idea that two birds breathing could hurt our chances put things on a little too vivid a basis. Only Lomax seemed unaffected. He shoved back now, and stood up.

"Some tests I have to make, Captain. I have an idea that might turn up the killer among us!"

I had an idea he was bluffing, but I kept my mouth shut. A bluff was as good as anything else, it seemed.

At least, it was better than anything I seemed able to do. I prowled over the ship, sometimes meeting Peters doing the same, but I couldn't find a bit of evidence. The crewmen sat watching with hating eyes. And probably the rest aboard hated and feared us just as much. It wasn't hard to imagine the man who was behind it all deciding to wipe one of us out. My neck got a permanent crimp from keeping one eye behind me. But there wasn't a shred of evidence I could find.

In two more days, we began to notice the stuffiness more. My breathing went up enough to notice. Somehow, I couldn't get a full breath. And the third night, I woke up in the middle of my sleep with the feeling something was sitting on my chest; but since I'd taken to sleeping with the light on, I saw that it was just the stuffiness that was bothering me. Maybe most of it had been psychological up until then. But that was the real thing.

The nice part of it was that it wouldn't be sudden—we'd have days to get closer and closer to death; and days for each one to realize a little more that every man who wasn't breathing would make it that much easier for the rest of us. I caught myself thinking of it when I saw Bullard or Grundy.

---

Then trouble struck again. I was late getting to the scene this time, down by the engine room. Muller and Bill Sanderson were ahead of me, trying to separate Hal Lomax and Grundy, and not doing so well. Lomax brought up a haymaker as I arrived, and started to shout something. But Grundy was out of Muller's grasp, and up, swinging a wrench. It connected with a dull thud, and Lomax hit the floor, unconscious.

I picked Grundy up by the collar of his jacket, heaved him around and against a wall, where I could get my hand against his esophagus and start squeezing. His eyeballs popped, and the wrench dropped from his hands. When I get mad enough to act that way, I usually know I'll regret it later. This time it felt good, all the way. But Muller pushed me aside, waiting until Grundy could breathe again.

"All right," Muller said. "I hope you've got a good explanation, before I decide what to do with you."

Grundy's eyes were slitted, as if he'd been taking some of the Venus drugs. But after one long, hungry look at me, he faced the captain. "Yes, sir. This guy came down here ahead of me. Didn't think nothing of it, sir. But when he started fiddling with the panel there, I got suspicious." He pointed to the external control panel for the engine room, to be used in case of accidents. "With all that's been going on, how'd I know but maybe he was gonna dump the fuel? And then I seen he had keys. I didn't wait, sir. I jumped him. And then you come up."

Wilcox came from the background and dropped beside the still figure of Lomax. He opened the man's left hand and pulled out a bunch of keys, examining them. "Engine keys, Captain Muller. Hey—it's my set! He must have lifted them from my pocket. It looks as if Grundy's found our killer!"

"Or Lomax found him!" I pointed out. "Anybody else see this start, or know that Lomax didn't get those keys away from Grundy, when he started trouble?"

"Why, you—" Grundy began, but Wilcox cut off his run. It was a shame. I still felt like pushing the man's Adam's apple through his medulla oblongata.

"Lock them both up, until Dr. Lomax comes to," Muller ordered. "And send Dr. Napier to take care of him. I'm not jumping to any conclusions." But the look he was giving Lomax indicated that he'd already pretty well made up his mind. And the crew was positive. They drew back sullenly, staring at us like animals studying a human hunter, and they didn't like it when Peters took Grundy to lock him into his room. Muller finally chased them out, and left Wilcox and me alone.

Wilcox shrugged wryly, brushing dirt off his too-clean uniform. "While you're here, Tremaine, why not look my section over? You've been neglecting me."

I'd borrowed Muller's keys and inspected the engine room from, top to bottom the night before, but I didn't mention that. I hesitated now; to a man who grew up to be an engineer and who'd now gotten over his psychosis against space too late to start over, the engines were things better left alone. Then I remembered that I hadn't seen Wilcox's quarters, since he had the only key to them.

I nodded and went inside. The engines were old, and the gravity generator was one of the first models. But Wilcox knew his business. The place was slick enough, and there was the good clean smell of metal working right. I could feel the controls in my hands, and my nerves itched as I went about making a perfunctory token examination. I even opened the fuel lockers and glanced in. The two crewmen watched with hard eyes, slitted as tight as Grundy's, but they didn't bother me. Then I shrugged, and went back with Wilcox to his tiny cabin.

---

I was hit by the place before I got inside. Tiny, yes, but fixed up like the dream of every engineer. Clean, neat, filled with books and luxuries. He even had a tape player I'd seen on sale for a trifle over three thousand dollars. He turned it on, letting the opening bars of Haydn's Oxford Symphony come out. It was a binaural, ultra-fidelity job, and I could close my eyes and feel the orchestra in front of me.

This time I was thorough, right down the line, from the cabinets that held luxury food and wine to the little drawer where he kept his dress-suit studs; they might have been rutiles, but I had a hunch they were genuine catseyes.

He laughed when I finished, and handed me a glass of the first decent wine I'd tasted in months. "Even a small ozonator to make the air seem more breathable, and a dehumidifier, Tremaine. I like to live decently. I started saving my money once with the idea of getting a ship of my own—" There was a real dream in his eyes for a second. Then he shrugged. "But ships got bigger and more expensive. So I decided to live. At forty, I've got maybe twenty years ahead here, and I mean to enjoy it. And—well, there are ways of making a bit extra...."

I nodded. So it's officially smuggling to carry a four-ounce Martian fur to Earth where it's worth a fortune, considering the legal duty. But most officers did it now and then. He put on Sibelius' Fourth while I finished the wine. "If this mess is ever over, Paul, or you get a chance, drop down," he said. "I like a man who knows good things—and I liked your reaction when you spotted that Haydn for Hohmann's recording. Muller pretends to know music, but he likes the flashiness of MÖhlwehr."

Hell, I'd cut my eye teeth on that stuff; my father had been first violinist in an orchestra, and had considered me a traitor when I was born without perfect pitch. We talked about Sibelius for awhile, before I left to go out into the stinking rest of the ship. Grundy was sitting before the engines, staring at them. Wilcox had said the big ape liked to watch them move ... but he was supposed to be locked up.

---

I stopped by Lomax's door; the shutter was open, and I could see the big man writhing about, but he was apparently unconscious. Napier came back from somewhere, and nodded quickly.

"Concussion," he said. "He's still out, but it shouldn't be too serious."

"Grundy's loose." I'd expected surprise, but there was none. "Why?"

He shrugged. "Muller claimed he needed his mate free to handle the crew, and that there was no place the man could go. I think it was because the men are afraid they'll be outnumbered by your group." His mouth smiled, but it was suddenly bitter. "Jenny talked Pietro into agreeing with Muller."

Mess was on when I reached the group. I wasn't hungry. The wine had cut the edge from my appetite, and the slow increase of poison in the air was getting me, as it was the others. Sure, carbon dioxide isn't a real poison—but no organism can live in its own waste, all the same. I had a rotten headache. I sat there playing a little game I'd invented—trying to figure which ones I'd eliminate if some had to die. Jenny laughed up at Muller, and I added him to the list. Then I changed it, and put her in his place. I was getting sick of the little witch, though I knew it would be different if she'd been laughing up at me. And then, because of the sick-calf look on Bill Sanderson's face as he stared at Eve, I added him, though I'd always liked the guy. Eve, surprisingly, had as many guys after her as Jenny; but she didn't seem interested. Or maybe she did—she'd pulled her hair back and put on a dress that made her figure look good. Either flattery was working, or she was entering into the last-days feeling most of us had.

Napier came in and touched my shoulder. "Lomax is conscious, and he's asking for you," he said, too low for the others to hear.

I found the chemist conscious, all right, but sick—and scared. His face winced, under all the bandages, as I opened the door. Then he saw who it was, and relaxed. "Paul—what happened to me? The last I remember is going up to see that second batch of plants poisoned. But—well, this is something I must have got later...."

I told him, as best I could. "But don't you remember anything?"

"Not a thing about that. It's the same as Napier told me, and I've been trying to remember. Paul, you don't think—?"

I put a hand on his shoulder and pushed him back gently. "Don't be a damned fool, Hal. I know you're no killer."

"But somebody is, Paul. Somebody tried to kill me while I was unconscious!"

He must have seen my reaction. "They did, Paul. I don't know how I know—maybe I almost came to—but somebody tried to poke a stick through the door with a knife on it. They want to kill me."

I tried to calm him down until Napier came and gave him a sedative. The doctor seemed as sick about Hal's inability to remember as I was, though he indicated it was normal enough in concussion cases. "So is the hallucination," he added. "He'll be all right tomorrow."

In that, Napier was wrong. When the doctor looked in on him the next time, the big chemist lay behind a door that had been pried open, with a long galley knife through his heart. On the bloody sheet, his finger had traced something in his own blood.

"It was...." But the last "s" was blurred, and there was nothing more.