The searcher-priest had no intention of unanchoring the ambulator's nether end or even slowing down. It had a score of strides on Xantcha when its brass foot touched the black circle. With its second step, it crossed the midpoint and sank between-worlds. Too fast. Too fast, memory warned from the back of Xantcha's mind; the priests had told them to enter the ambulators slowly, lest they get caught between two worlds.

Expecting an explosion, Xantcha skidded off the trail and hid behind the largest tree she saw. There was no explosion, but when she poked her head around the tree trunk fire rippled across the ambulator disk's surface. She had no idea if the priest had survived. For that matter, Xantcha didn't know if the ambulator had survived. Urza wouldn't welcome the sight of her, not when he'd told her to stay far away, but Xantcha thought it best to warn him. She stepped in front of the dragon when it burnt a path through the trees. Urza shot flame to the left of her and flame to the right. Xantcha ran until she was breathless, then circled back. The dragon sat beside the ambulator; the saddle-seat between its shoulders was empty.

Urza had gone to Phyrexia alone.

Xantcha settled down to wait. Morning became afternoon. The sky darkened, and the dragon's eyes shone red.

Urza returned, not through the ambulator but in a blaze of lightning, and Xantcha did nothing to attract his attention as he remounted the dragon. Moments later they

were gone.

The storm ended quickly. The ambulator beckoned. It wasn't broken. For the last time, Xantcha asked herself:

Was her heart important enough to risk everything to rescue it? The priests lied about so many things; only a fool could believe they hadn't lied about newt hearts. Try as she might, Xantcha couldn't remember exactly what hers had looked like; mottled amber, perhaps, with bright rainbow inclusions. She'd only seen it that once and never seen another. Only a fool. .. And she was a fool.

On hands and knees, Xantcha crept up to the ambulator and was surprised to discover that the searchers had left the prime end in the forest. She began unanchoring it, careful not to disturb the hard panel where seven jet-black jewels were set in a silver matrix. When the ambulator was loose and rippling, Xantcha yawned. There was a single sharp pain in her gut as the cyst contracted- drawing the armor out twice in a single day wasn't what Urza had in mind when he made the cyst, but she could do it five times, at least, before the process failed. The not-quite-liquid flowed beneath her clothes.

She stepped into the unanchored ambulator. It swirled around her, not unlike the armor itself. By the time she'd reached the middle, the black disk had shrunk to half its size and risen to her waist. Xantcha had repressed how much she disliked the ambulators. The sinking and suffocating was worse than following Urza between-worlds, and the cyst made the passage worse. It swelled in her gut; she thought she might explode before her head emerged in Phyrexia.

Because she'd unanchored the prime end in the forest, the nether end in Phyrexia was also loose and shrank as Xantcha emerged. Any Phyrexian would have been suspicious of a newt who rolled up a ambulator behind it. The avengers that normally guarded the Fourth Sphere field, where scores of ambulators were anchored, would have annihilated her on sight, if there had been any left standing. Xantcha assumed that Urza had annihilated them as he emerged; at least, something had.

Waste not, want not, the Fourth Sphere was even uglier than she remembered with acrid air and oily ash drizzling from the soot clouds overhead. The roar of a thousand furnaces was less a sound than a presence, a vise tightened over her ribs. The hollow where the ambulator had been anchored was bright with bilious yellows, noxious greens, and an iridescent purple that was the very color of disease. Nothing was alive, of course; it was just filthy oil, slicked over an eon of detritus not fit for even the furnaces.

There wasn't a living Phyrexian, newt or otherwise, in sight.

Grateful, but suspicious of her good fortune, Xantcha retrieved the glossy disk from beneath her feet: the rolled-up ambulator. Holding it by its flexible rim, she twisted her wrists in opposite directions. The disk rippled and shrank until it was scarcely larger than her palm, with the jewels protruding on both sides.

After tucking the ambulator between her belt and her armor, Xantcha took her bearings. There was no sun-star for Phyrexia, especially not here, in the Fourth Sphere. Away from the furnaces, light came harsh, constant and without

shadows. But the place was home, or it had been, and it came back to her.

A few strides up the greasy slope, the horizon expanded and Xantcha saw why her return to Phyrexia had been so easy: straight ahead, in the direction of the Fane of Flesh, the soot clouds had turned red and fire fell from the sky.

Urza? Xantcha asked herself and decided it was possible that Urza was burning his way through Phyrexia. The ambulators could be anchored anywhere. Once unrolled, they were tunnels, direct passages from one specific place to another, no detours allowed, but a 'walker made his own path here, there and everywhere. Urza could change his mind between-worlds, but whenever, wherever, he ended his 'walk, he stood on a world's surface. In Phyrexia, the surface was the First Sphere.

When she'd dwelt in Phyrexia, before she'd known the meaning of silence, Xantcha had been able to ignore the furnace roar. She reached within herself to remember the trick and realized she'd been gone from Phyrexia several times longer than she'd been a part of it. But the memory was there. Xantcha numbed herself to the ambient rumbling and heard the clanging alarms.

She smiled. Those alarms were struck when a furnace was about to blow. Every Phyrexian had an emergency place, and for newts that place was the Fane of Flesh, precisely where she wanted to go. Of course, the emergency wasn't a furnace, and the closer she got to the sprawled hulks of furnaces, fanes, and gremlin shanties, the clearer it was that in the absence of the expected disaster, panic had replaced plan.

Priests and other compleated types that Xantcha didn't remember, and possibly, had never seen, raced through gremlin town. Their voices were shrill enough to hurt. The challenge was staying out of their way; the shambles were already littered with gremlins who'd failed.

Urza's armor protected Xantcha from the sky; her sense of purpose did the rest. The Fane of Flesh wasn't the most impressive structure in the Fourth Sphere, but it stood near the glistening oil fountain, which had become a spire of blue-white flame.

A phalanx of demons made their appearance while Xantcha threaded her way through the maze of furnaces. Narrow beams of amber and orange shot upward from their torsos, into the reddest clouds. Urza answered with lightning. In the Fourth Sphere's filthy skies, the air itself ignited and a web of fire shot to every part of the horizon. Xantcha felt the heat through her armor. Her instinct was to run, but ash quickly followed the fire, and the Fourth Sphere went dark.

For a moment, flesh had the advantage over metal, at least flesh protected by Urza's armor. Neither ash nor smoke irritated Xantcha's eyes, and with a bit of effort she could see a body's length in front of her. As in the gremlin town alleys, the danger came from the panicked and the fallen: no one paid any attention to a stray newt, assuming they could see her.

Then the demons regrouped. A low humming sound began in the distance, followed by a cold wind that scoured the air. As it passed overhead, Xantcha looked up and saw the bottom of the Third Sphere, a sight she'd never seen before. She