In the forty-eight hours since his mother went missing, Alex had discovered only one thing: Even the most important mission can be sidelined by a well-meaning aunt.

Alex was stuck in his new “room,” which was actually his uncle’s office. He was playing Dragon Stryke II: Out of the Sun on a semi-ancient computer and waiting until it was late enough for him to sneak out. His dragon crested a mountain peak. Alex flapped its wings one more time and then took a quick look out the window at the old, rusty fire escape. Will that thing even hold me? When he looked back, his dragon was engulfed in flames.

He scanned the screen to see where the attack had come from. It had come from out of the sun, of course. A fire-breathing red dragon had swooped down from above. Alex watched the crumpled, smoking frame of his lightning-breathing blue dragon crash into the mountaintop. In the end-of-game quiet, he listened carefully. Aunt Adele was still in the hall complaining loudly about one of her coworkers.

Alex looked around the room and saw the confines of his new world. The thin foam mattress he slept on was rolled up in the corner. His clothes were stuffed into an old cardboard box marked Taxes, and Legend of the Death Walkers was propped up by the window along with a few of his mom’s other things.

He turned back to the computer and hit reset on the game. His blue dragon re-formed in midair and breathed out its trademark lightning bolt. The dragon was brand-new, all the damage from the last game gone. A fresh start: full health. Just like me, he thought, scanning the sky for enemies.

The TV blared to life out in the living room and was briefly muted. “Alex! TV!” screamed Adele.

“No thanks!” he shouted back. “Playing Dragon Stryke! Probably going to turn in early! Tired!”

The volume roared back to its normal, neighbor-shaking level. Alex locked the door and checked the time: a little past seven thirty. He was running late. He saved the game, turned off the light, and grabbed his backpack.

Alex pushed the chair in and stepped over to the window. He tried to be quiet. The old window groaned but slid up with surprising ease. But as soon as the window opened, the door did, too. Alex looked back. It was his cousin Luke. His room was on the other side of the thin office wall. Busted, thought Alex. His cousin had been surprisingly cool to him so far, but Alex figured that was over now.

“Where you going?” said Luke. Dressed in his standard array of workout gear, he looked like an ad for Under Armour.

“Uh, nowhere?” Alex ventured.

“Yeah, right,” said Luke. “Don’t sweat it. Why do you think that window slides open so easy? I use it, too.”

“So you’re not going to …” Alex couldn’t bring himself to say “tell.” It sounded too babyish around his cool, cocky older cousin.

“Nah,” said Luke. “Just wanted to let you know there’s a missing step halfway down. Kind of dangerous in the dark, so watch out.”

And just like that, he was gone.

Alex slid one leg through and stepped gingerly onto the battered metal fire escape. The whole structure swayed slightly and Alex glanced back into the safety of the office.

What the heck, he thought. You only live twice.

He slid the window closed behind him and crept carefully over to the steep metal stairs. The fire escape swayed a little more, but he climbed down to the second-floor platform without the whole thing peeling off the building. The missing step was tricky, but he got past it without breaking anything thanks to Luke’s warning. An extendable ladder led down to the alleyway. It let out a single, strangled-cat screech as Alex pushed it down. A light came on in the window next to him and he scampered down quickly without risking a look.

The ladder ended a good four feet above the alleyway. Alex lowered himself and dropped. He landed safely next to the recycling bins, then straightened up, wiped his hands on his jeans, and headed out into the darkening city.

Alex turned the corner and jogged to the bus stop. There was an emergency staff meeting at the Met, after hours at 8:00 p.m. “Crisis control,” Ren had called it. Everyone involved in the new exhibition would be there, packed into the main conference room. Everyone. That was their window of opportunity — apart from his actual window — and he couldn’t be late.

The M96 bus pulled up two minutes later. He got a seat and tried to think about absolutely anything other than his mom. “You have powerful magic, my son. You have summoned the Ancient Ones …” He shook his head so sharply that the man sitting next to him shifted subtly away.

He took that day’s New York Post out of his backpack to reread the story. “Trouble at the Met: Cursed Exhibit or Pyramid Scheme?” Their piece on the heist and his mom’s disappearance had been serious, but this one was written mostly for laughs. He already knew the parts about the “sleepless mummy” and “tipsy jars,” so he skipped down and reread the end: The Met isn’t the only famous museum having mummy issues. The Museum of Egyptian Antiquities in Cairo was recently shut down due to what officials there dubbed “mass psychosis.”

He stuffed the paper back in his pack. It reminded him of the news reports from the morning he’d woken up: blood rain, night turning to day. Now the Lost Spells had been stolen, his mom was missing, and an entire museum was closed.

But that was wrong. He knew it was wrong. His mom’s disappearance wasn’t an item on a list. It was the list. It was the paper it was written on and the pen it was written with. His mom’s absence was everything. And Alex would do anything to find her.

“What took you so long?” asked Ren.

It was 8:03. She was holding the door to the staff entrance open.

“I literally could not have gotten here any faster!” Alex protested. “I ran all the way from the bus stop.”

“You ran? From the crosstown stop?”

“Yeah.”

Ren frowned. “You need to be careful. You have your medicine, right?”

He ignored the question. It wasn’t his own health he was worried about now. The thought that his mom might be suffering had entered his mind, and now it refused to leave. She might be tied up in the dark or hurt or —

“We need to be quiet,” Ren cautioned as they headed into the shadowy hush of the closed museum. “It echoes less if we walk along the walls.”

But they barely made it a hundred yards before they were spotted.

“Where are you two going?” said Oscar. Alex had always liked Oscar. The guard had been working at the museum for ages, had seen them grow up — and basically let them do whatever they wanted.

“Dad has a meeting,” said Ren.

“Yeah, I heard about that. I’m sure they’ll get all this straightened out.”

“How’d you get that?” said Ren, staring at the clean white cast on Oscar’s hand.

The guard looked embarrassed. “Honestly? No idea,” he said. “Think I must have fallen and hit my head and my hand at the same time. That’s my best guess, anyway. I did have a headache.”

“Can we sign it?”

Oscar shook his head. “Not professional,” he said. “How you doing, Alex?”

Alex gave him a weak thumbs-up.

“He doesn’t like to talk about it,” said Ren, tugging him along.

“Course,” said Oscar. “You two take care. And don’t set off any alarms on the way to the office.”

“We won’t!” promised Ren as they headed toward the elevator.

As soon as Oscar turned the corner, they changed course and hurried on toward the Egyptian wing.

“I guess it’s only the guards assigned to the new exhibition who are in the meeting,” whispered Alex.

“Yeah,” said Ren, looking around like they were in lion country. “We’ll have to be more careful.”

They avoided a second guard near the main entrance and made it to Egypt by 8:10.

The wing was dim and quiet. Alex felt a chill ripple through him as they edged deeper into the half-light. This was no longer friendly terrain, no longer his mom’s extended office. This was a crime scene now. A place where he’d seen things. At least he thought he had. Those last moments before his collapse seemed like a dream to him now.

“Watch out for scorpions,” said Ren.

Alex knew it was supposed to be a joke, something to break the tension, but neither of them laughed. The eerie quiet wrapped around them. Alex could hear Ren’s hushed breathing between the soft slap of their footsteps. It was a silence that reminded him they were on their own: no help, no witnesses.

“Okay, so the police have been all over this place,” he said. Even at half his normal volume, his voice seemed to fill the room. “And then the cleaning crews.” He side-eyed the little tomb where he’d collapsed, and picked up his pace.

“Slow down,” said Ren. “You always … you, like, practically run by that thing.”

“I just don’t like it,” he said. He remembered the feeling of lying on the cold floor, the helplessness. The jackal’s eyes. But he didn’t let his thoughts get sidetracked this time. “So we’re not going to find anything, like, lying on the floor. But we might see something out of place or …”

“I know,” said Ren. “I have some theories.”

Alex watched her pull a notebook from her messenger bag.

“What did you do, make a list?”

“Two pages,” she said. Alex looked over and saw the neatly printed items filling the first page. Back in school, Ren was always making lists. She didn’t show them to anyone else, because she knew they’d make fun of her. Plus Ten Ren. But she showed them to Alex, because she knew he wouldn’t. All it proved to him was that he had the right partner.

“First I want to show you the little mummy,” she said. “Because it’s freaky.”

The curtain was up over the doorway, but there was no guard in front of it. There honestly wasn’t much left to guard. Alex wasn’t sure he wanted to step through, but Ren’s busy efficiency made him feel safer somehow.

“Speaking of freaky,” he said as they walked past the Stung Man’s sarcophagus.

They passed the empty case in the next room and headed straight into the side room that held the mummy child. Alex had seen it just a few days earlier, and he noticed the change immediately. Alex stared at it through the glass. “You know what it looks like?” he whispered.

“What?”

“Like it can’t sleep. Like it’s trying to get comfortable.”

“She,” said Ren. “Like she can’t sleep. The sign says she was a little girl who died from disease.”

“You’re not making this any less spooky,” said Alex.

“Spooky,” said Ren, holding up her notebook, “is not on the list.”

“Okay then, what is?”

“Okay, first clue: cameras. They’re everywhere” — she waved the notebook in the general direction of the ceiling — “but the detective told you there was nothing on them.”

“So?”

“So, step one: blind spots. We need to figure out where they are, and what might have happened in them.”

Both kids looked up at the security cameras around the room.

“Wait,” said Alex. “Do you hear that?”

Ren cocked her head, lifting one ear slightly to listen. “Sounds like cereal in a box.”

“Or dirt in a shovel,” offered Alex.

“But where’s it —”

They both turned and looked back down at the little mummy.

She was looking right at them.

Her whole body had shifted, and her empty eye sockets gazed blankly up at them.

“Holy —” began Alex.

“What the —” began Ren, her voice rising.

And that’s when the entire museum went dark.

Someone screamed. Alex thought it was Ren, but he could not rule out the possibility that it was him.

Or the mummy.

“The power went out!” shouted Ren, her voice stretched with panic.

Alex heard her footsteps as she slowly backed away from the coffin in the darkness. He did the same, his hand stretched out behind him, feeling for the wall.

“What do we do?” said Ren.

Alex looked around but saw only blackness. He knew this wing well, but well enough to find his way out in the dark?

As if in answer, an emergency light clicked on along the far wall, casting a weak glow that left much of the room in shadow. Alex could hear the faint sound of far-off shouting as employees and guards scrambled to follow the museum’s blackout protocols: securing the exits and the most valuable paintings.

“Ren, let’s get out of here!” he called.

She was already moving.

They sprinted through the room where the Lost Spells had been, but they came to a halt in the one housing the Stung Man. A harsh grinding sound filled the room. In the weak glow of another emergency light, they couldn’t see where the noise was coming from.

“What is that?” said Ren, nervously scanning the room.

Alex saw it now. He opened his mouth, but nothing came out. He did manage to point. Ren followed his finger — straight toward the Stung Man’s sarcophagus.

She took a quick, sharp breath, but her voice failed her, too.

They both watched in silent horror as the heavy stone lid of the Stung Man’s sarcophagus slowly slid back.