Elidee drifted over to an especially dark section of wall and flew in a little circle in front of it.
"Okay," I said. "I guess this is where we get in."
"What is where we get in?" Billy asked, his voice skeptical. "Get into where?"
"Undertown," I said. I ran my hands over the wall. To the casual touch it appeared to be bare, unfinished concrete, but I felt a slight unsteadiness when I pressed against it. It couldn't have been solid stone. "Must be a panel here somewhere. Trigger of some kind."
"What do you mean, 'Undertown'? I've never heard of it before."
"I was probably working here for five or six years before I did," I said. "You have to understand the history of Chicago. How they did things here."
Billy folded his arms. "I'm listening."
"The city is a swamp," I said, still searching for a means of opening the door with my fingertips. "We're darn near level with Lake Michigan. When they first built the place, the town kept sinking into the muck. I mean, every year it sank lower. They used to build streets, then build a latticework of wood over them, and then another street on top of that, planning on them slowly sinking. They planned houses the same way. Built the front door on the second floor and called it a 'Chicago entry, so when the house sank, the front door would be at ground level."
"What about when the street sank?"
"Built another one on top of it. So you wound up with a whole city existing under the street level. They used to have a huge problem with rats and criminals holing up under the streets."
"But not anymore?" Billy asked.
"The rats and thugs mostly got crowded out by other things. Became a whole miniature civilization down here. And it was out of sight of the sun, which made it friendly space for all the night-crawling critters around."
"Hence, Undertown," Billy said.
I nodded. "Undertown. There are a lot of tunnels around Chicago. The Manhattan Project was housed in them for a while during World War Two. Did all that atomic bomb research."
"That's cheerful. You come down here a lot?"
I shook my head. "Hell, no. All kinds of nastiness lives down here."
Billy frowned at me. "Like what?"
"Lots of things. Stuff you don't often see on the surface. Things even wizards know almost nothing about. Goblins, spirits of the earth, wyrms, things that have no name. Plus the usual riffraff. Vampires sometimes find lairs down here during the day. Trolls can hide here too. Molds and fungi you don't get in most of the natural world. You name it."
Billy pursed his lips thoughtfully. "So you're taking us into a maze of lightless, rotting, precarious tunnels full of evil faeries and monsters."
I nodded. "Maybe leftover radiation, too."
"God, you're a fun guy, Harry."
"You're the one who wanted in on the action." My fingers found a tiny groove in the wall, and when I pressed against it a small, flat section of stone clicked and retracted. The switch had to have triggered some kind of release, because the section of wall pivoted in the center, turning outward, and forming a door that led into still more dank darkness. "Hah," I said with some satisfaction. "There we go."
Billy pressed forward and tried to step through the door, but I put a hand on his shoulder and stopped him. "Hang on. There are some things you need to know."
Billy frowned, but he stopped, listening.
"These are faeries. We'll probably run into a lot of the Sidhe, their nobles, hanging out with the Winter Lady. That means that they're going to be dangerous and will probably try to entrap you."
"What do you mean, entrap me?" Billy said.
"Bargains," I said. "Deals. They'll try to offer you things, get you to trade one thing for another."
"Why?"
I shook my head. "I don't know. It's in their nature. The concept of debt and obligation is a huge factor in how they behave."
Billy lifted his eyebrows. "That's why that little guy worked for you, right? Because he owed you for the pizza and he had a debt to you."
"Right," I said. "But it can work both ways. If you owe them something, they have a conduit to you and can use magic against you. The basic rule is not to accept any gifts from them - and for God's sake, don't offer them any gifts. They find anything other than an equal exchange to be either enticing or insulting. It isn't a big deal with little guys like Toot, but if you get into it with a Sidhe Lord you might not live through it."
Billy shrugged. "Okay. No gifts. Dangerous faeries. Got it."
"I'm not finished. They aren't going to be offering you wrapped packages, man. These are the Sidhe. They're some of the most beautiful creatures there are. And they'll try to put you off balance and tempt you."
"Tempt me? Like with sex, is that what you're saying?"
"Like any kind of sensual indulgence. Sex, food, beauty, music, perfume. When they offer, don't accept it, or you'll be opening yourself up to a world of hurt."
Billy nodded. "Okay, got it. Let's go already."
I eyed the younger man, and he gave me an impatient look. I shook my head. I don't think I could have adequately conveyed the kind of danger we might be walking into with mere words in any case. I took a deep breath and then nodded to Elidee. "All right, Tinkerbell. Let's go."
The tiny scarlet light gave an irritated bob and then darted through the concealed doorway and into the darkness beyond. Billy narrowed his eyes and followed it, and I went after him. We found ourselves in a tunnel where one wall seemed to be made of ancient, moldering brick and the other of a mixture of rotting wooden beams, loose earth, and winding roots. The tunnel ran on out of the circle of light from my amulet. Our guide drifted forward, and we set out to follow her, walking close together.
The tunnel gave way to a sort of low-roofed cavern, supported here and there by pillars, mounds of collapsed earth, and beams that looked like they'd been added in afterward by the dwellers in Undertown. Elidee circled in place a bit uncertainly, then started floating to the right.
I hadn't been following the little faerie for five seconds before the skin on the back of my neck tried to crawl up over my head and hide in my mouth. I drew up short, and I must have made some kind of noise, because Billy shot a look back at me and asked, "Harry? What is it?"
I lifted a hand to silence him and peered at the darkness around me. "Keep your eyes open," I said. "I don't think we are alone."