But when a more powerful being or a wizard swears an oath by his own power, the effect is magnified significantly. Too many broken oaths and promises can cripple a wizard's use of magic, or even destroy the ability entirely. I've never seen or heard of a wizard breaking an oath sworn by his own power. It was one of the constants of the preternatural world.

"And by my own power, I swear in return to abide by the terms of the agreement," I said.

"Harry," Thomas hissed. "What the hell are you doing?"

"Saving our collective ass, I hope," I said.

"You don't actually think he'll abide by it, do you?" Thomas whispered.

"He will," I said, and as I said it I realized how confident I was that I was right. "If he wants to survive, he doesn't have much choice. Grevane's entire purpose here is gaining power. He won't jeopardize that now by breaking an oath sworn by his magic."

"You hope."

"Even if he decides to screw us, it's good to keep him talking. The longer we delay, the more likely it is the cops are going to show up. He'll back off before he faces that."

"But if the cops don't show, you're giving him what he needs to make himself into a freaking nightmare," Thomas said.

I shook my head. "Might not be a bad thing. I can't beat him. Corpsetaker, either. Throwing Grevane into the mix is going to make it harder for either of them to concentrate on me."

Thomas exhaled slowly. "It's a hell of a risk."

"Oh, no. A risk," I said. "Well, we wouldn't want that, now, would we?"

"No one likes a wiseass, Harry."

"Butters is counting on me," I said. "Right now, I'm all he's got. Do you have any better ideas?"

Thomas grimaced and shook his head.

"Very well," Grevane called. "How shall we proceed?"

"Pull your zombies back," I said. As I did, I found a pen and a piece of paper, pulled out the folded piece of paper from my pocket, and made a copy of the numbers. "You go with them. Liver Spots and Butters wait by the car. We all get in and drive off. Once I'm a few blocks away, I'll drop Liver Spots off with the numbers, unharmed."

"Agreed," Grevane said.

We waited for a minute, and then Thomas said, "You hear anything?"

I went to the door and Listened. I could hear someone breathing fast and heavy. Butters. Nothing else. I shook my head and glanced at Thomas.