Lithe and watchful, Daria crawled atop a huge ceramic pipe. It gurgled with a river of oil. The ceramic was cold beneath her fingertips. Just above her shoulder, stone tubes glowed in a hot tangle. They seared her back. Had she been mortal, she would have been dead already. Even as an immortal, she suffered dreadfully in this caustic place. For the first time since doffing it, she wished she had her titan suit, but it could never have navigated the third sphere of Phyrexia. The place was an endless jumble of pipes, as deep as an ocean and as wide as a world. Rarely did the tubes run more than a man's height away from each other. In most places, they formed a maze of inescapable cages. Pits held piles of bleached bone. The flesh of those unfortunates had fed monsters that even now stalked Daria. Metal claws skittered on the pipe behind her. The beasts only waited for her to wander into one trap or another before they converged to feed.

Daria intended to disappoint them.

Ducking her head, she slid through a narrow gap. She would have passed easily if not for the bomb strapped to her back. It hung up on a fitting. Heat poured in a vicious wave over her. Gritting her teeth, Daria flattened against the lower pipe and struggled free. She pulled herself through. There was enough space now to stand. Climbing to her feet, she ran along the pipe.

Ahead glowed a huge column, the confluence of a million power pathways. Daria felt its radiance on her skin and in her mind. The energy in that pillar created a spaciotemporal distortion that prevented planeswalking. It was a natural defense. These conduits were the most vulnerable points on the third sphere. A single bomb, like the one strapped to Daria's back, would destroy a section of pipe a hundred miles in diameter.

It was dirty work, and hot, but it needn't have been. Without breaking stride, Daria thought away the sweat on her brow. This body was only a projection of her mind, but sometimes a distracted mind allowed its body to follow natural courses.

The pipe took a sharp bend downward. Daria leaped from the end of it. She allowed momentum to carry her across the yawning pit. Her feet came down at a run atop a cluster of tubes. She ran into the glowing aura of the power column.

Energy pressed on her and flowed around her. It was like running through hot water. Power dragged her hair backward. Soon the strands would burn away. With a thought, Daria formed her hair into a helmet. Her battle vest thickened and grew to a heat-resistant hauberk. Even her exposed skin darkened and hardened. Nictitating membranes covered her eyes.

The central core was just ahead. Running, Daria unstrapped the bandoleer that held the bomb. She swung the thing up before her. Twisting the conic tip of the device, she activated it. Her feet slowed. The dynamic flux was almost unbearable. She held the bomb out into the streaming energy. There was no need to affix the device. It would cling like a magnet to a construct of such power.

The air became gel-like. Daria consciously ceased breathing. Her scaly hand pressed the bomb inward. At last, it touched the solid edge of the column. There it clung.

She backed away a few paces before turning. It felt good to have the bomb gone from her back. It felt good to have the heat push her outward. She cast a shadow before her. Daria walked, looking at her hands in their black carapace.

"I look almost like Szat," she mused.

Something moved on the twist of pipes ahead, something black and huge. It must have been one of the bone pickers that had been following her. It approached.

In reflex, Daria tried to planeswalk away. She could not, mired in the spacio-temporal fluxes.

It would be a fight then. Daria set her feet in a crouch. She extended her left arm. Her sleeve grew into a long, thick shield. Lifting her right arm, she formed the air around into a blazing sword. The helmet on her head grew a gleaming visor. She was ready.

The beast bounded toward her. It was huge and black- a dragon engine. Its hackled back scraped the pipes. A barbed tail lashed behind it. A fangy mouth gaped before it. Corruption welled up between the creature's teeth.

There was something familiar about that face. Before she could make it out, a ball of acid hurtled from the toothy maw.

Daria raised her shield. It grew to cover her whole front. Acid splashed across it, striking the pipes above and below. The inky stuff dissolve them. Steam hissed from the pipe overhead and oil gushed from the pipe underfoot.

Daria fell back, lest she plunge through the ceramic and into the open channel. Her shield was gone, but it had saved her life-for a moment.

With a thunder of talons, the dragon was upon her.

Daria swung her sword out. Its hilt became a haft, which she rooted on the pipe. Its blade jagged into a huge pike. The edge struck the dragon's breast and cut through scale and meat and bone to organs beneath. This was no dragon engine, but an actual dragon. Ducking under the soaring belly, Daria wrenched her pike sideways. It macerated the monster's liver. Bile sprayed out over her. The beast's momentum carried it overhead. It crashed atop a tangle of pipes. Daria's pike jutted from its heart.

It wasn't dead. That blow would have killed any normal dragon, even a dragon engine, but this was something more. It yanked the pike from its breast. Sinew and scale closed over the wound. The creature sat up. When its head lifted, at last Daria knew who hunted her.

"Tevash Szat," she growled, her eyes narrowing. "What are you doing here?"

Climbing to his feet, the planeswalker stalked forward. His tail lashed fitfully. "I should think that utterly obvious. I'm doing to you what I did to Kristina."

Shaking her head ruefully, she said through gritted teeth, "I should have known." She leaped backward over the break in the oil pipe. Her hand lashed out, hurling a spell. There was very little mana in this sphere-it was the reason she had not cast a spell before-but this effect needed only the mildest of power. Fire rushed down into the pipe. It ignited the oil, hurling up a wall of flame. Daria turned and ran. The flames burst the pipe behind her, introducing more air. The fire redoubled. It would be racing the other direction as well, toward Szat. Flame would force him back toward the power column, would trap him there until Daria could escape its aura and planeswalk to the others.

She ran. There was no other escape. Pipes burst behind her. Fire lashed her feet and blasted against her hauberk. The narrow passage was just ahead. If she could reach it, if she could dive through…

Mantled in flame and hoary with wounds, Tevash Szat surged up suddenly behind her. His jaws spread wide. His teeth clamped down. They pierced her through the head and throat and chest. They went straight through her and met. Claws scooped up the severed lower half. Wings surged once more.

Then Szat was gone. He had planeswalked away with his meal. He would take time to eat it, to heal the burns across his body before returning to the others.

Then he would reappear within his titan engine and wait for his next victim.

Urza had chosen this section of the fourth sphere because it was intensely black. There was no better place to hide eight titan engines. The blackness also meant that most beasts avoided the spot. Only stupid things approached. Urza had been visited by twenty-some scuttling gremlins-dog-sized creatures with white claws and red eyes. They crushed just fine underfoot…

Urza's engine stepped on two more. He scraped the tripod sole on metallic ground.