Ren watched in horror as the flat stone of the wall began to bulge outward into a bubble of pale stone about six feet up. She didn’t realize it was a face until the sunken eyeholes took shape and the neck began to push outward underneath it. Then came the shoulders, then the chest.

The head pulled free of the wall with a wet tearing noise that sounded more like meat than stone. The rest of the body dragged itself free of the wall, leaving no indentation, no indication whatsoever that a section of stone the size and shape of a ragged human body had been removed.

Its steps were stiff and uneven. Chunks of stone flaked off and fell to the ground with each bend and flex. The creature stopped, crossed its stony arms in front of it, and pointed its featureless visage toward the sky above.

There was a soft cracking sound.

“Turn away!” called Todtman, covering his face with his hands and turning his back on the macabre spectacle. As he turned, his bad leg gave out and he crumpled to the ground.

Ren rushed over to help, but as she did, there was a muffled crash — like thunder heard from under a blanket — and rock exploded outward from the Walker. Limestone dust turned the entire pit white, and here and there Ren felt the sting of larger chunks against her skin.

She heard Alex cry out but could see nothing. Her eyes stung from the powdered stone, and when she tried to call Alex’s name, thick white dust filled her mouth. She convulsed into hacking coughs and covered her face.

As the heavy dust settled to the ground, she risked a peek back. The Walker’s true form was revealed. It looked like death itself: a ragged mummy — or most of it, anyway. The wrapping was mostly torn away, and some pieces of the body were missing. A few of the fingers were just gone, but the larger gaps had been filled in with clay and pale stone. Half its skull was clay, much of its torso was stone, and none of it quite fit or matched. For eyes, it had two white stones.

And yet it moved. And yet, somehow, it lived. It took a step forward and drew in a long, rasping breath. In the warm desert air of the pit, Ren went cold to the tips of her toes. As the Walker’s chest expanded, a few remaining sections of rib rose beneath the shabby wrapping. Even the limestone that made up the rest of its chest seemed to flex and breathe.

Ren, on the other hand, felt as if a horse was sitting on her chest. Fear constricted her breathing. The other Walkers had looked scary, sure, but they’d also looked alive. They’d come back, and they had the skin and clothing to prove it — even if that skin was sometimes burned or swollen.

Todtman spoke softly, his voice colored by both awe and fear: “This Death Walker is older than the others, beyond ancient. Made when the mummification process was still crude. And whatever he was buried in must have given out. This one’s been in the ground. Its body has calcified.”

Ren eyed the vein of living limestone in its chest — stone meeting bone — and felt the same sense of unreality she always did when confronted with the brazen illogic of magic. It felt like floating free from the world she knew, with nothing to grab on to, nothing to stop her from floating away so far that she’d never find her way back.

And as the creature took another step forward and Ren took another step back, she realized that it might be true this time. She might never get back to the world she knew: home.

Here, at the end, the homesickness that had grown inside her since she left New York became a razor-sharp ache. She’d never sit in the Met again, staring at her beloved Rembrandts and knowing her dad was somewhere nearby. Knowing that she could go ask him for ice cream money or just hang out and watch him work. She realized she’d never have another “girls’ day” with her mom, going to Serendipity and getting “drippity” sundaes.

“Marr fesst dol!” croaked the Walker, snapping Ren back to the overheated reality of the pit. Like the others, Ren already had her hand around her amulet. Normally, that allowed them to understand the ancient Egyptian of their adversaries. Not now.

“Can you understand it?” she asked.

“A lost tongue,” said Todtman.

Ren peered into the creature’s open mouth as it spat out more inscrutable syllables and saw that its real tongue was lost, too, replaced by a thick slab of clay. The thing flicked and curled with the liveliness of a fat brown toad. Ren wanted to vomit.

The Walker took another step forward; the friends took another step back — only to find their backs were nearly to the wall. Soon they would find out what terrible, deadly power this Walker possessed. Unless … Her mind flashed back to midnight in Vienna. If that shadow creature had been out of place in this world, well, then this earthenware weirdo definitely was.

“Stand back!” she said to her friends. “Cover your eyes!”

She squeezed the ibis tight in her left hand and called on its power once more. She thrust out her right hand. There was a quick white flash and then … nothing. What had seemed so mighty at night amounted to little more than a camera flash in the daylight flooding the pit. The Walker flinched slightly.

And then it attacked.

The Walker rushed forward, its stone-patched legs moving with surprising fluidity. “Split up!” called Ren.

Alex turned to run — and couldn’t! He stared down, incredulous. The floor of the pit was solid stone, but he felt his feet sinking down into it as if it were mud. He watched in terror as the stone reached the laces of his boots. He could hear the creature’s footsteps heading toward him, and he tried desperately to lift first one leg and then the other. Nothing. He could only squirm as his feet sank farther.

He saw Ren struggling, too. Her head and shoulders turned to rush along the wall, but her lower half refused to follow.

Only Todtman had managed to stay a step ahead. A vine of stone rose up and grabbed the heel of one of his black dress shoes, but with one hand on his amulet, he swept the other downward, shattering the stone shackle.

Alex followed his example, squeezing the scarab hard and then forming his other hand into a fist and smashing it down directly over each foot in a quick one-two. He felt like he’d just dropped a bowling ball on each foot, but he heard two muffled cracks and quickly pulled his feet up through the powdered stone.

He turned and saw that the Walker was just a few yards from Ren now, already stretching out one bony three-fingered hand. Stuck in the floor, all she could do was stare at the approaching horror with eyes gone round with fear.

“No,” Alex breathed. He felt a sudden, achingly sharp sense of responsibility for his friend’s safety. She had followed him halfway around the world, through one peril after another, and he could not let anything happen to her now. He rushed toward both of them.

“Hey, stone-face,” he shouted desperately at the creature. It turned and regarded this new threat with pale eyes. Alex battled back his fear and squeezed his amulet hard, but before he could use it, a slab of stone shot out from the back wall of the pit, like a dresser drawer opening outward. It cracked Alex hard in the side and slammed him to the ground.

He landed with a loud “Ooouff!”

He rolled over and scrambled to his feet. The stone grabbed at him the whole time, but by moving fast, he was able to stay out of its rough grip —

The Walker’s shadow fell over him.

Alex stumbled back and to the side to create some space. Left hand on his amulet, Alex pointed the fingers of his right hand into a spear and lashed out at the Walker with a whipping, whistling column of super-charged wind. If this creature is really of the earth, thought Alex, let’s see how it handles some erosion!

Bits of clay and chunks of stone chipped and slipped off. Another finger sheared off the Walker’s right hand and went flying end over end out of sight. The ancient menace roared into the unrelenting gale and stumbled backward a few steps. Alex narrowed his eyes, tightened his fingers, and stretched his arm out farther. His head pounding, his body aching from the force channeled through it, he willed the wind to increase.

He stared directly into the two white stones pressed into the clay-patched front of the Walker’s skull and saw the evil there. What he did not see, until it was too late, was the creature raising a now two-fingered hand, palm down, and slamming it hard toward the ground.

The pit floor pulsed like the skin of a bongo drum. The force was so strong Alex could feel it in his teeth, and he found himself tossed two feet into the air. He crashed down on his back and smacked the tender bump on the back of his head. Looking up, he saw stars spiraling in the blue sky above.

A moment later, his head cleared.

It was a moment too long. He desperately tried to sit up, to take hold of his amulet again — but he was pulling against stone. The pit floor had already encircled him with its tendrils, and now he felt himself sinking back into it. Legs, arms, pinned.

He was helpless.

Todtman, however, was still free and using his amulet to fight back. A lance of invisible force carved into the creature, blowing a clean, round hole in its torso. Alex’s hopes rose, even as his body sank. He heard Ren let out a triumphant “Yes!”

But the Walker didn’t so much as look down, and as its next step touched the pit floor, Alex saw limestone flowing like liquid up the creature — from foot to leg to body — filling in the hole. “Oh no,” whispered Alex, his arms and legs now fully encased in stone and only his chest, neck, and head still above it.

Todtman steeled himself for another attack, his eyes wide, seeking out the next threat. Would it come from below? Behind?

Above.

A chunk of stone no bigger than a baseball broke off the top edge of the pit. There was a faint whistling sound, Todtman looked up, and …

KLONK!

The stone hit him smack in the forehead, and he hit the ground like a sack of potatoes. The pit floor immediately encircled and immobilized him.

Alex’s heart sank. He had failed both his friends, and he knew what came next. Death Walkers fed on the souls of the living — and they were messy eaters. The earthen entity surveyed its three trapped foes. It watched them struggle uselessly against the pit’s stony grip, like a finicky diner perusing a menu, deciding what to eat first.

A flash of white light made up its mind. “No, Ren!” called Alex, but it was too late. The Walker headed directly for her, closing the distance in long, hungry strides. She released another blast of white light. It was weaker this time, and had even less effect. But then —

“Mmmm-rack?”

Pai stepped into view, brushing past Ren’s sunken legs and sitting down directly between Ren and the Walker. Alex had forgotten all about Pai. It was easy to do with an enchanted feline who had a habit of vanishing abruptly. But at the moment, Pai wasn’t going anywhere.

“Mmm-RACK!” she repeated, not as a question this time.

The mummy cat’s vocabulary might not stretch much past one word, but her meaning seemed clear enough: Over my long-dead body.

The Walker looked down and opened its mouth. It took Alex a few moments to recognize the hoarse rasp that came out as a laugh.

“No, Pai,” Ren said softly. “Go.”

Alex saw the tears in his best friend’s eyes and felt guilt stab into him again. Others had died on this quest, but he didn’t think he could take it if she did. She was only here to help him, and now … He struggled as hard as he could against the stone all around him, jerking one way and then the other. The stone didn’t even hint at budging.

“Get out of there, Ren!” called Todtman from his own confinement. “Try to free one foot at a time!”

But the stone was up past Ren’s ankles now and neither foot would budge. Her last line of defense was an undead temple cat — which the Walker now casually flicked aside. He waved his hand and a two-foot-tall wave rose in the stone floor, heading straight for Pai, moving fast.

The mummy cat hissed and raised one bony paw, but the stony wave overwhelmed her. Her small body was carried off and — SSPLACKK! — smashed hard into the back wall of the pit. As the stone sank back into the ground, Pai wobbled upright, but she barely had time to look up before the next strike. A ten-foot-tall stone column crashed down on her with enough power to crush a car. As it receded, her little body lay motionless along the wall, bent in ways it should not have been.

“Noooo!” cried Ren.

And then everything changed.

In the middle of a cloudless day, a strange darkness fell over the pit.