The revenant swayed a little, its bones grinding faintly as it moved. From its throat came a low growl.

Spaulding felt a ripple of terror like ice water down his back. Growling? That was new. It didn’t seem good.

He scooted across the bed so fast he fell out the other side, stumbled to his feet, and dashed for the door.

The creature snatched at him as he passed. Leathery fingers wrapped around his arm.

Spaulding wrenched hard against its grip. The revenant held on tighter—but the strain was too much for its decomposing hand. With a wet shlurp, Spaulding’s arm slipped free.

He shuddered, holding his damp arm away from himself. “I’m going to have to disinfect everything in this whole room,” he muttered.

As he opened the door, a whiff of rot hit his nostrils and a chorus of moans and groans arose from the hallway. Great—more of them. It was dark in the hall, but from what he could see, it was pretty crowded.

Behind him, the revenant in his room sidled closer, clacking its finger bones greedily.

He was trapped.

An angry hissing broke out in the hall. Underlying the stench of death, Spaulding caught the familiar scent of rodents and alligator handbags. Then a long, heavy form swooped down from above, sending the undead flying like bowling pins.

“David Boa!” Spaulding cried.

The boa constrictor had apparently been sleeping on top of the bookshelf in the hall, and he didn’t seem too pleased that his nap had been interrupted. Within seconds, he had the revenants in the hall hopelessly entangled. The one in Spaulding’s room tried to make a break for it, but the snake sank his teeth into the creature’s leg and dragged it to the ground with the others.

While David busied himself with squeezing his victims, Spaulding edged past, heading for Aunt Gwen’s room. “Thanks!” he called over his shoulder. The snake gave a self-satisfied flick of his tongue.

Spaulding wasn’t sure exactly what he was going to tell her—Hey, Aunt Gwen, sorry I didn’t mention this before, but I’m being stalked by the dead?—but it was clear he had to tell her something. If revenants were going to be attacking them in their own home, it was just too dangerous to keep her in the dark any longer.

“Aunt Gwen! Wake up!” He lifted a fist to bang on her door, but it swung open at the first touch.

His heart began to pound. He flicked on the light. It cast a warm glow over the rumpled, empty bed.

“Aunt Gwen?” he whispered.

Across the room, the curtains stirred in a breeze from the open window. But Aunt Gwendolyn was always cold. She never left her window open at night.

Slowly, Spaulding crossed the room and looked out. The yard below was empty. The street was silent.

“Aunt Gwen . . .” he repeated hopelessly.

Spaulding wasn’t sure how long he’d been standing at the window, his mind blank, before the silence was broken by the sound of bare feet on pavement. Marietta and Lucy raced up the street.

“Spaulding!” Marietta waved frantically. Lucy was silent, her face streaked with tears.

“I’m coming!” he yelled.

Back in the hall, there was no sign of David or his captives—he must have dragged them off somewhere to dispose of them in private.

Outside, Lucy sobbed as Spaulding ran up. “They took our dad, Spaulding!” She clutched Daphne to her chest tightly. “What are we going to do? Why would they take him?”

“They took Aunt Gwen, too.” He realized he was shivering, both from the cold—he was only wearing his pajamas—and from sheer panic.

“What about Kenny?” Lucy sniffed.

Spaulding’s heart sank. She was right. Poor Kenny was mixed up in this, too. “We have to go check on him.”

But Marietta shook her head. “No. This has gone way too far. We have to go straight to the police.”

“And tell them what?” Spaulding wrapped his arms around himself against the chilly air. “We’ve been over this. They’ll never listen.”

“But now they’d have to listen! There’s hard evidence—our families are missing.”

“Yeah, and how do we get them to believe that we know where they are? We say the undead kidnapped them and we know who the necromancer is? That’ll be really convincing. Look, we don’t have time to argue about this. We need to get to Kenny’s house, fast. Then we can figure out what to do next.”

Marietta scowled, but she didn’t argue anymore. She and Lucy went back to their house to get their bikes and slip on sneakers, and Spaulding did the same. While he was in his room, he grabbed his backpack and threw in his flashlight, notebook, and anything else that seemed as if it might come in handy.

A few minutes later, they met up again in front of Spaulding’s house. There was a brief delay while they discussed whether Lucy could bring Daphne,

As Spaulding mounted his bike, an imperious voice rang out behind him. “Just a moment there!”

He turned to see Mr. Radzinsky glaring at him, his head thrust through the wall of his house. Marietta flinched at the sight of him, and Lucy cowered behind Daphne.

The ghost eyed the girls a little guiltily. “Hello again, you two. No need to be alarmed.”

“But you don’t want us to see you!” Lucy squeaked from behind her instrument case.

Mr. Radzinsky harrumphed and smoothed his hair. “Ah, yes. I suppose I was a bit touchy about that the last time we met. But I’ve turned over a new leaf. I’m trying to get out more, make new friends—being dead is no reason not to have a social life, eh? Heh!”

The girls laughed nervously at Mr. Radzinsky’s little joke and edged farther away as soon as he wasn’t looking.

The ghost turned to Spaulding. “Now, Spaulding, where is David? He went to your house over an hour ago.”

“Yeah, I saw him. Actually, he saved my life. A bunch of revenants tried to kill me, but he protected me.”

Mr. Radzinsky couldn’t hide a smile. “Well! I’m not surprised. He is very assertive. But if you see him again, send him home directly.”

Spaulding nodded and turned away.

“Hold on there.” The ghost leaned farther out of his wall, squinting. “What is that peculiar aura around you?”

Spaulding looked down at himself. T-shirt, striped pj pants, feet . . . nothing seemed to have an aura.

“I can’t quite make it out from here . . .” Mr. Radzinsky waved him closer. “Ah, yes, that’s it—there’s a bug on you.”

“What? Ew! Get it off! Get it off!” Spaulding squealed, slapping at his hair and pajamas.

The ghost somehow managed to roll his eye sockets. “Not that kind of bug. Someone’s watching you.” He crooked his finger for Marietta to come closer. “Look at his head, right there. You see it?”

Marietta leaned forward to look closer. “Oh, gross—there is something . . .”

Spaulding felt her tug at his hair just above his ear. Then she held something out on her fingertip for him to see. It didn’t look like much more than a whitish speck until he took it from her and brought it right up to his eye.

“Is it electronic or something?” he asked Mr. Radzinsky.

“Heavens, no. It reeks of black magic. You’ve heard of spells that use part of a person—hair or fingernail clippings or some such—to put a hex on them? This is similar, except in this case the spell uses a part of the spell-caster, not the victim. It’s made of someone’s skin.”

“Ew!” Spaulding threw the thing down and stomped it into the dirt, rubbing at his head where it had been.

“By attaching a fragment of himself to a victim, the sorcerer is able to observe anyone he chooses. It’s magical surveillance.” Mr. Radzinsky checked Lucy and Marietta and assured them they were clean. He frowned at Spaulding. “Where did you run into someone powerful enough to do that kind of magic? I question the company you’re keeping, I really do.”

Spaulding scratched his head again—his skin still felt crawly at the thought of the bug being stuck to him since who-knew-when. “I think it’s the same person who’s been causing the disturbance in the world of the dead you mentioned before. I guess they can do more than just necromancy.”

Mr. Radzinsky crouched down to look at the bug more closely. “Perhaps you’d better get away from this device before we discuss things any further. I think—”

Before he could finish, the bug began to glow faintly red. There was a crackle like electricity, and a spark of reddish light jumped from the bug to the ghost. Mr. Radzinsky looked down at his chest, patting anxiously at himself where the spark had disappeared. “Oh, dear,” he said.

“What was that?” Lucy whispered.

Mr. Radzinsky was trembling faintly. The trembling rapidly became twitching. His head began to wrench from side to side. Then a strange, hollow voice spoke. It came from Mr. Radzinsky, but it wasn’t his usual voice at all.

“Return . . .” the voice hissed. “Return what you have stolen . . .”

Everyone backed away from the ghost except Spaulding. He steeled his nerves and took a step forward. “Mr. Radzinsky?” he whispered, cautiously stretching a hand toward him.

Mr. Radzinsky shuddered, his body curled up in midair as if he was racked with pain. Then he suddenly straightened up, like he’d thrown something heavy off his shoulders.

“Not . . . not me,” he gasped in his normal voice. “Sorry—trying to fight it—” He broke off with a choking sound.

“The red mercury!” Lucy said, clutching Spaulding’s arm. “You said it gives control over the dead!”

Spaulding nodded. “You’re right—I guess that means power over ghosts, too.”

Mr. Radzinsky hunched over again, his face hidden in his hands. Slowly, he lifted his head to look at them—but he did it by twisting his head around backward and upside-down. His eyes were glowing a deep, pulsating red.

“Return what you stole, little boy,” he said in a nasty sing-song, “or Auntie and Daddy are going to die.”

Then he winked out, like a match dropped in water.

Lucy burst out crying again. Spaulding felt like he was frozen in place, staring at the empty air where Mr. Radzinsky had been.

A vise-like hand landed on his shoulder. He flinched and whirled around, half-expecting to see a revenant or the possessed version of Mr. R staring back at him, but it was worse: a very angry-looking Marietta.

“What,” she said through her teeth, “exactly have you done?”