Naya’s face fell. “It’s gone.”

“The slime,” Detroit said. “This is where we saw it.”

“I definitely don’t see any slime,” Scout said, cramming beside me in the doorway. She was right. I mean, we were underground, so it wasn’t like it was sparkling clean in there, but there was definitely no slime.

Detroit looked crestfallen. “I don’t understand. This is really where we saw it. It couldn’t have just disappeared.”

Jason gestured toward the double doors at the other end of the corridor, which were marked with those pointy biohazard stickers. “No,” he said. “But someone could have cleaned up the slime.”

“Reapers?” I wondered. “You think the Reapers know something about the creatures?”

“Maybe, maybe not,” he said. “After all, we didn’t, not until we saw them last night.” He looked at Michael. “What can you tell us?”

Michael nodded decisively, then rubbed his hands together like he was getting ready to roll some dice. He stepped forward into the corridor, put a palm flat against the wall, and closed his eyes.

“It’s muddy,” he said. “Unclear. So many coming and going. So much birth and death. Change . . .” But then he shook his head.

“I can’t read anything else clearly.” When he opened his eyes again, there was defeat there. “I can’t see anything else.”

“What does that tell you?” Scout asked, tilting her head at him. “What does it mean if you can’t read anything?”

Michael shook his head, clearly flustered by whatever he’d seen—or hadn’t seen. “Could be that too much went on—too much magic for any one message to filter through. Or could be some kind of blocking spell.”

“We’ve seen those before,” Detroit agreed. “Spells to erase the magic’s fingerprints, scramble the magic’s DNA. Reapers use obfus for things like that.”

I lifted a hand. “Sorry. What’s an ‘obfu’?”

“Obfuscator,” Detroit explained. “Something that obfuscates—makes it hard for Michael to get a read on the building.”

“Any chance you’ve got a magic detector in your bag of tricks?” Scout asked.

“Oh!” Detroit said, fumbling through the pockets of her leather jacket until she pulled out something tiny and black that was shaped like a pill. She held it up between two fingers.

“Magic smoke,” she said. After Scout pulled Michael back into the doorway, Detroit leaned forward and tossed the pill into the hallway.

It hit the concrete floor and rolled a little, finally settling against the double doors.

“Four, three, two, and—”

Before she could say “one,” the pill emitted a puff of blue smoke. As it rose through the far end of the corridor, we could see pale green lines crisscrossing the air, like dust highlighting a laser beam.

“What is that?” I wondered.

“Trip wires,” Scout said. “Magical trip wires. And I have got to get one of those spells.”

“I’ve got a box at the Enclave,” Detroit whispered. “I’ll bring you a couple.”

“We are now besties,” she whispered.

“What do they do?” Michael asked.

Scout pointed toward the smoke. “They set wards,” she said. “They’re like trip wires. If we breach one as we try to cross the door, whoever set the spells them gets a signal. Like an alarm bell.”

“And I bet Reapers would be on us in nothing flat,” Jason predicted. “This has got to be their handiwork. I mean, it’s got to be someone with magic, and if this was an Adept hidey-hole, we’d know about it.”

“Well, we’re definitely not going in there looking for slime,” Michael said. “What’s plan B?”

“I am,” Naya said. “I will call someone.”

“One of the recently deceased,” Detroit clarified, gesturing toward Naya. She took a step out of the crowded doorway into the corridor, blew out a slow breath and moved her hands, palms down, in front of her as she exhaled like she was physically pushing the air from her body.

Jason bumped my arm. “Let’s set up a protective area while she’s getting ready,” he said, then pointed to each of us in turn. Michael and Scout made a line between Naya and the wooden door into the tunnels, and Jason and I stepped around them all to create a barrier between Naya and the trip wires. Two lines of Adept defense in case something nasty popped through either way.

Once in position, we waited silently, gazes skimming nervously around the corridor, waiting for something to happen.

As if the air conditioner had suddenly kicked on, the temperature in the room dropped by ten or fifteen degrees. I stuffed my hands into my pockets. “It’s super-chilly down here today.”

All eyes turned to me. Understanding struck, and the hair at the back of my neck lifted. The corridor felt like a field of power lines, abuzz with potential energy.

“That wasn’t just a breeze, was it?” Michael whispered.

The sidewalk grates began to vibrate, then clank up and down in their moorings as something moved into the corridor. The air got hazy, and a cold, thick fog sank down among us.

“She’s here,” Naya whispered.

Jason muttered a startled curse, then reached out for my hand. I laced my fingers with his and squeezed. Michael and Scout were also holding hands. About time.