"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?"