"Grevane killed him," Mab guessed.

"And how."

"This mortal ferromancy—technology, you called it. Does it yet conceal the book?"

"Yeah."

"Grevane yet seeks it?"

"Yeah. Him and at least two more. Cowl and the Corpsetaker."

Mab lifted a pale hand and tapped a finger to rich, lovely lips the color of frozen mulberries. Her nails were colored with shining opalescence gorgeous to the eye and distracting as hell. I felt a little dizzy until I forced myself not to look at them. "Dangerous," she mused. "You have fallen among deadly company, mortal. Even the Council fears them."

"You don't say."

Mab narrowed her eyes, and a little smile graced her lips. "Impudent," she said. "It's sweet on you."

"Gosh, that's flattering," I said. "But you haven't told me a thing about why they might be interested in the Erlking."

Mab pursed her lips. "The being you ask me about is to goblins as I am to the Sidhe. A ruler. A master of their kind. Devious, cunning, strong, and swift. He wields dominion over the spirits of fallen hunters."

I frowned. "What kind of spirits?"

"The spirits of those who hunt," Mab said. "The energy of the hunt. Of excitement, hunger, bloodlust. Betimes, the Erlking will call those spirits into the form of the great black hounds, and ride the winds and forests as the Wild Hunt. He carries great power with him as he does. Power that calls to the remnants of hunters now passed on from mortal life."

"You're talking about ghosts," I said. "The spirit of hunters."

"Indeed," Mab said. "Shades that lay in quiet rest, beyond the beck of the mortal pale, will rise up to the night and the stars at the sound of his horn, and join the Hunt."

"Powerful shades," I said quietly.

"Specters most potent," Mab said, nodding, her eyes bright and almost merry as they watched me.

I leaned on my staff, trying to get as much weight as I could off of my injured leg, so that it would stop pounding enough to make me think. "So a gaggle of wizards whose stock in trade is enslaving the dead to their will is interested in a being whose presence calls up powerful spirits they couldn't otherwise reach." I followed the chain of logic from there. "There's something in the book that tells them how to get his attention."

"Darling child," Mab said. "So clever for one so young."

"So what is it?" I asked. "Which part of the book?"

"Your godmother," she said, her smile growing wider, "has no idea."

I ground my teeth together. "But you do?"

"I am the Queen of Air and Darkness, wizard. There is little I do not."

"Will you tell me?"

She touched the tip of her tongue to her lips, as if savoring the taste of the words. "You should know us better than that by now, wizard. Nothing given by one of the Sidhe comes without a price."