"Not at all."

"Or with the axe, for that matter, if you have that hidden somewhere about you."

"As a matter of fact, I lost it."

"Then if you do not mean to ambush me-and yet you're lying in wait, as if you distrust me-then it must be that you want to talk. You want to know if I will help you turn against Lord Atwood."

"Thank G.o.d, Mr Vaz. Thank G.o.d. That certainly saves time. Yes. Two against two is better than three against one."

"I did not say yes. The two of them have rifles, and we have nothing-not even an axe. Do you have a plan?"

"I don't suppose I do. Element of surprise; that's all."

"And then? Without Atwood, how will we get home?"

"We won't, Mr Vaz. We won't."

"I see." Vaz picked up his candle again, and held it up, studying the recesses of the room. Shadows moved from window to window.

"After a while," he said, "one ceases to hear the wind. Lord Atwood promised me a ship of my own, you know."

Arthur patted his pockets. "I can't even offer you a cigarette, I'm afraid."

"Let's think. There are four of us at present. Nine when we started; four now. Bad luck all round, old chap. I have counted six of the-the natives. That is half again as many as four, and it would be twice three if Payne joins us, and three times two if he does not."

"They mean us no harm. It's Atwood they want to stop. But he's dug in-they can't get to him. They need our help. I think perhaps they'll help us, if it comes to it."

"There is also the small matter of right and wrong, Mr Shaw. What you are proposing is murder."

"He means to do something dreadful. We-all of us-we are only ... Mr Vaz, I saw Josephine."

Vaz raised an eyebrow.

"She's alive. I swear to you. She spoke to me. She knows his plans, and she spoke to me."

"And what did she tell you, Mr Shaw?"

When they returned to the Gallery, Atwood and Payne were waiting by the windows. Payne marched briskly up to them.

"About b.l.o.o.d.y time. Where've you layabouts been hiding? It's now or b.l.o.o.d.y never, so pull yourselves together."

Payne shoved a rifle into Arthur's hands and seized Vaz roughly by his elbow, as if he were an errant schoolboy. Vaz slapped his arm away and Payne scowled and cuffed Vaz's ear. Arthur hit Payne under his chin with the b.u.t.t of the rifle. He toppled backwards and his head struck the window-sill with an awful crack.

Atwood was already gone. At the first sign of violence he'd turned and fled, throwing himself on his belly down the tunnel that led to his cell.

Arthur crouched by the side of the chute, peering down to see lamplight at the bottom of it.

Atwood's voice called up from below.

"My last trial, then. In the form of you, Mr Shaw, and you, Mr Vaz."

"Stop talking like that, you b.l.o.o.d.y lunatic."

"Remember that I have a pistol down here, Shaw. If I see your head coming down that chimney, I will shoot it off."

Arthur crept over to the window, where Vaz was inspecting Payne's body.

"I think he is probably dead," Vaz whispered.

Arthur couldn't bring himself to care either way. He doubted anyone back on Earth had ever loved Payne very much.

"Atwood's right," he whispered. "He's dug in there, the b.a.s.t.a.r.d."

"I can hear you both quite clearly," Atwood said.

Arthur swore, picked up a chunk of stone, and threw it down the tunnel.

Atwood laughed. "Don't be ridiculous, Shaw. You're not thinking clearly, either of you. But listen. Listen."

Atwood's voice became friendly, ingratiating. "You're afraid, I know. You're tired. Good Lord, don't you think I'm tired? The human body, the mind, they're not made for this place. For the things we've seen. I know that you hear the voices of despair, the voices of madness. No wonder. But don't falter now. Shaw-don't falter now! Josephine depends on you. Josephine-"

"She's alive, Atwood. I spoke to her."

Arthur heard Atwood shifting about in his cell. He crept over to the side of the tunnel. Over by the window, Vaz readied Payne's rifle.

"He's mad, you know, Vaz," Atwood said. "Shaw has gone mad."

There was another long silence, except for footsteps and the sc.r.a.ping of stone below.

"I didn't know," Atwood said. "I didn't know that she was alive. I'm very pleased. I never intended what happened to her."

"Come out. Come out and we can talk this out."

"That was a nasty-looking blow you struck Payne, Shaw. I didn't know you had it in you. Is he dead?"

Arthur didn't answer.

"Yes," Vaz said.

"Come out, Atwood. Come out and talk. Tell us what you're planning to do. I think-I think perhaps you've become confused, Atwood."

There was a noise of sc.r.a.ping stone.

"One of us is mad," Atwood called up. "Not me. Perhaps I shouldn't have brought you here, Shaw. I thought you were strong enough. Now I see I made a mistake."

Arthur glanced at Vaz. His face was set, apparently unmoved by Atwood's words.

"Come out, Atwood."

"And if I do?"

"Then we'll let bygones be bygones. We can work together to get home."

"Home!" Atwood's laughter echoed up from the cell. "Home? We three, gentlemen-we have conquered Mars. We are the greatest magicians ever to have lived. And you want to go home."

"Conquered? Not without help, I think, Atwood. What did they promise you to bring you here?"

Atwood stopped laughing.

"Answers, Shaw. I was promised answers. If I closed the circle. And I nearly have, Shaw; I have nearly unlocked the puzzle. A little more time. That's all."

"Answers? And what did you promise them?"

There was another long silence.

"One world for another," Vaz said. "Is that right, Lord Atwood?"

Atwood called, "Is Josephine really alive, Shaw?"

"Come out, Atwood, and I'll take you to her."

There was no answer.

Vaz crept closer. The silence deepened. Lamplight reflected steadily on the tunnel's walls.

"Are you there? Atwood, d.a.m.n you, are you there?"

"It is a disgusting thing to do," Vaz said, "but these are desperate times."

He picked up Payne's body by the shoulders. For an awful moment Arthur thought he was suggesting cannibalism, as if they were shipwrecked sailors. Then he indicated by pointing that Arthur should take Payne's feet, and pointed a pistol at Payne's head, from which Arthur understood that he was proposing to throw Payne down the tunnel, in the hope that Atwood, if he was still there, would reveal himself by shooting the corpse.

They threw Payne head first. Nothing happened.

The experiment was inconclusive.

Arthur swore and threw himself down. He landed on Payne's body and scrabbled to his feet, expecting a bullet at any moment.

The cell was empty. The lantern, abandoned in the middle of the floor, illuminated a spiral of tablets etched with deeply shadowed carvings.

The rifle came clattering down. Vaz followed it.

At the far corner of the cell there was another tunnel, just large enough for a man to crawl into. They hadn't known it was there. Last time Arthur was in the cell, Atwood had leaned the tablets against the wall to hide it.

They got down on their hands and knees and gave chase.

A little way along its length the tunnel began to slope upwards, and soon it turned into a smooth vertical chimney. Faint light beckoned at the top of it. It was narrow enough to climb. It would be a death-trap if Atwood began shooting down into it. But they were committed now.

They had to leave the rifle. They shouldered their way up.

After what felt like hours they emerged onto a rooftop. The courtyard was to their left. They looked out across a square expanse of stone, made chaotic by dust-dunes and by collapse-a steeplechase of fallen obelisks and weirder ornamentation. In the distance, the rooftop swelled up into the cracked stone egg of the castle's dome. Beyond that the mountain, and tremendous black clouds. There was moonlight-the pale moon was rising behind the mountain.

Arthur saw Atwood in the distance, dodging fallen masonry. He had his pistol in one hand and held his papers precariously under his arm. Overhead, bright blue wings struggled through the storm towards him. There were two of them-no, three or more. Perhaps one of them was Josephine-Arthur couldn't tell. Atwood fired his pistol. The sound was a dull crack over the howl of the storm. One of the Martians jerked, wings spasming, and fell from the sky.

Arthur charged, sliding in the dust, leaping over great holes that opened up into utter darkness below, roaring nonsense.

Atwood turned and pointed the pistol at him. Arthur kept running. The pistol wavered in Atwood's hand, between Arthur and the Martians overhead. Atwood looked more frustrated than frightened, as if he were thoroughly annoyed with himself for the tactical blunder of fleeing the safety of the cell and exposing himself to the Martians. He fired at Arthur once and then turned and ran. He darted erratically across the uneven rooftop, clambering over obstacles and jumping over chasms. Wings swooped towards him; he ducked behind a pillar. Then he was off and running again. Arthur kept chasing him. Blue wings harried him back and forth. He saw Vaz running too, though they'd been separated by the wind and by various obstacles. Now Vaz was attempting to flank Atwood, as if they were playing a rough sort of sport. Atwood seemed to be searching for a window or bolt-hole by which he could return to the safety of the castle's interior.

Atwood came to the edge of the roof. The dome rose on the other side of a narrow chasm. Atwood stopped as if considering jumping. It was clearly impossible without dropping his papers. Instead he turned, pointing his pistol at Arthur across an empty and shelterless expanse of rooftop.

Josephine circled behind Atwood and swooped, meaning to kill. He stepped lightly aside, dancing along the edge of the rooftop, as if some sixth sense had warned him of her approach, or as if her shadow had betrayed her. She scrabbled in the dust and turned-faster than he was expecting-and struck the gun from his hand.

His eyes widened-not in alarm, but as if in recognition. He rubbed his bruised hand and smiled.

He opened his mouth. For a moment she thought he might be about to offer an apology, or an explanation. Instead, he lifted the papers in his hand, waved them, and shouted something that she couldn't hear over the wind. She lunged and struck the papers. The wind whirled them away, scattering some over the rooftops, swallowing others up into the shadows. Atwood looked around wildly. When he turned back to her, there was nothing in his expression but a cold inhuman hatred.

He raised his unbruised hand in a peculiarly unpleasant devil's-horn gesture-what was peculiar about it was that it seemed to involve too many fingers, or shadows of fingers. As she leapt towards him again, the wind picked up, seizing her with cold hands and sending her helplessly tumbling through the air, so that one moment she was staring up into the sky, the mountain above her like a whirlwind, and the next she was looking down at the castle, its mad turrets and arches and windows all askew. Somewhere off in the sky she saw Orpheus struggling in the same wind. Beneath her, Arthur and a ragged stranger approached Atwood across a chessboard of dense shadows.

Vaz, seeing the Martian strike the pistol from Lord Atwood's hand, shouted with hoa.r.s.e joy, jumped out from the stone he'd been sheltering behind, and ran, boot flapping, his head down and a hand up against the wind. Mr Shaw, he observed, was half a ship's length away and had fallen on all fours in a drift of dust-and no wonder, because it did seem that the whole castle had started to sway in the wind. If this was a dream, then this frantic chase was as good a way to end it as any. If he could just get his hands around Lord Atwood's throat, then perhaps he might wake with a jerk in London ... Or he might not. One way or another it would be over.

He looked up at the Martians, thinking he might wave to them, to acknowledge comradeship-they were beautiful creatures, who belonged in a bluer sky! He could hardly make them out. A whirlwind overhead flung them to and fro among clouds of dust; as he watched one of them seemed to plummet, wings broken by the wind, to slam into a sharp-cornered obelisk. That was an outrage. Distracted, he nearly stepped out into a hole in the rooftop. He teetered on the edge.

A long stone beam led across the chasm. At the other end of it he saw Atwood standing on the roof's edge, arms raised; it was hard to say whether he was conducting the winds, or whether the winds were jerking him about like a puppet. Vaz inched out across the beam, tightrope-walking. "Your Lordship," he called. "Your Lordship-one moment, if you please."

The wind had picked up, and he felt unsteady on his feet. When he was three-quarters of the way along the beam Atwood turned to him and gestured with one hand. Vaz took another step forward and the sole of his boot finally tore off, as if it had caught on a nail (there were no nails-as if some invisible hand had s.n.a.t.c.hed at it).

He threw himself forwards, in one of those great leaps that were possible only on Mars, and seized Atwood by his wrist. Atwood stumbled. It seemed to Vaz that the winds went still for a moment. Then Atwood pushed him backwards and his bare foot slid in the dust and he fell back through the hole in the roof.

He fell fifteen feet down into a drift of dust.

After catching his breath for a moment he stood, patted himself down, and looked around for a way back up. He was in a large, dark, dust-choked pentagonal room. When he lit one of his last remaining matches, he saw no obvious exits other than the hole far overhead. The far corners of the room were cloaked in shadow. There might be a door there; it was too early to panic.

Something moved in the darkness ahead and for an instant he saw them as they were now-the makers of this ruin. He saw them the way that sometimes one could quite clearly see a storm approaching on the horizon without quite knowing exactly what it was one had seen; perhaps nothing but a distant flickering, a certain bruised quality of the light. First they weren't there; then they were, whether one liked it or not, in their dozens, their hundreds, pressing together, their overlapping wings darker patches within the shadows of the room. They filled the whole castle, perhaps.

He closed his eyes and prayed and pushed through them. Cold; dry; fluttering; electrical. His prayer became a wordless moan. Slipping and sliding through the dust toward the wall he tried to recall the symbols of the Engine, Atwood's tricks of magical defense. He couldn't remember a b.l.o.o.d.y thing. Perhaps it was better that way. "Not a b.l.o.o.d.y thing! Ha! Not a thing."