Gard grunted. "c.r.a.p."

"c.r.a.p," I concurred.

The grendelkin had fled into Undertown.

Chicago is an old city-at least by American standards. It's been flooded, burned down several times, been constructed and reconstructed ad nauseam. Large sections of the city have been built up as high as ten and twelve feet above the original ground level, while other buildings have settled into the swampy muck around Lake Michigan. Dozens and dozens of tunnel systems wind beneath its surface. No one knows exactly how many different tunnels and chambers people have created intentionally or by happenstance, and since most people regard the supernatural as one big scam, no one has noticed all the additional work done by not-people in the meantime.

Undertown begins somewhere just out of the usual traffic in the commuter and utility tunnels, where sections of wall and roof regularly collapse, and where people with good sense just aren't willing to go. From there, it gets dark, cold, treacherous, and jealously inhabited, increasingly so the farther you go.

Things live down there-all kinds of things.

A visit to Undertown bears more resemblance to suicide than exploration, and those who do it are begging to be Darwined out of the gene pool. Smart people don't go down there.

Gard slashed a long opening in the fence with her ax, and we descended crumbling old concrete steps into the darkness.

I murmured a word and made a small effort of will, and my amulet began to glow with a gentle blue-white light, illuminating the tunnel only dimly-enough, I hoped, to see by while still not giving away our approach. Gard produced a small red-filtered flashlight from her duffel bag, a backup light source. It made me feel better. When you're underground, making sure you have light is almost as important as making sure you have air. It meant that she knew what she was doing.

The utility tunnel we entered gave way to a ramshackle series of chambers, the s.p.a.ces between what were now bas.e.m.e.nts and the raised wall of the road that had been built up off the original ground level. Mouse went first, with me and my staff and my amulet right behind him. Gard brought up the rear, walking lightly and warily.

We went on for maybe ten minutes, through difficult-to-spot doorways and at one point through a tunnel flooded with a foot and a half of icy stagnant water. Twice, we descended deeper into the earth, and I began getting antsy about finding my way back. Spelunking is dangerous enough without adding in anything that could be described with the word ravening ravening.

"This grendelkin," I said. "Tell me about it."

"You don't need to know."

"Like h.e.l.l I don't," I said. "You want me to help you, you gotta help me. Tell me how we beat this thing."

"We don't," she said. "I do. That's all you need to know."

That sort of offended me, being so casually kept ignorant. Granted, I'd done it to people myself about a million times, mostly to protect them, but that didn't make it any less frustrating-just ironic.

"And if it offs you instead?" I said. "I'd rather not be totally clueless when it's charging after me and the girl and I have to turn and fight."

"It shouldn't be a problem."

I stopped in my tracks and turned to regard her.

She stared back at me, eyebrows lifted. Water dripped somewhere nearby. There was a faint rumbling above us, maybe the El going by somewhere overhead.

She pressed her lips together and nodded, a gesture of concession. "It's a scion of Grendel."

I started walking again. "Whoa. Like, the the Grendel?" Grendel?"

"Obviously." Gard sighed. "Before Beowulf faced him in Heorot-"

"The Grendel?" I asked. " Grendel?" I asked. "The Beowulf?" Beowulf?"

"Yes."

"And it actually happened like in the story?" I demanded.

"It isn't far wrong," Gard replied, an impatient note in her voice. "Before Beowulf faced him, Grendel had already taken a number of women on his previous visits. He got sp.a.w.n upon them."

"Ick," I said. "But I think they make a cream for that now."

Gard gave me a flat look. "You have no idea what you're talking about."

"No kidding," I said. "That's the point of asking."

"You know all you need."

I ignored the statement, and the sentiment behind it to boot. A good private investigator is essentially a professional asker of questions. If I kept them coming, eventually I'd get some kind of answer. "Back at the pub, there was an electrical disruption. Does this thing use magic?"

"Not the way you do," Gard said.

See there? An answer. A vague answer, but an answer. I pressed ahead. "Then how?"

"Grendelkin are strong," Gard said. "Fast. And they can bend minds in an area around them."

"Bend how?"

"They can make people not notice them, or to notice only dimly. Disguise themselves, sometimes. It's how they get close. Sometimes they can cause malfunctions in technology."

"Veiling magic," I said. "Illusion. Been there, done that." I mused. "Mac said there were two disruptions. Is there any reason it would want to steal a keg from the beer festival?"

Gard shot me a sharp look. "Keg?"

"That's what those yahoos in the alley were upset about," I said. "Someone swiped their keg."

Gard spat out a word that would probably have gotten bleeped out had she said it on some kind of Scandinavian talk show. "What brew?"

"Eh?" I said.

"What kind of liquor was in the keg?" she demanded.

"How the h.e.l.l should I know?" I asked. "I never even saw it."

"Dammit."

"But . . ." I scrunched up my nose, thinking. "The sign from his table had a drawing of a little Viking bee on it, and it was called Caine's Kicka.s.s."

"A bee," she said, her eyes glittering. "You're sure?"

"Yeah."

She swore again. "Mead."

I blinked at her. "This thing ripped off a keg of mead and a girl? Is she supposed to be its . . . bowl of bar nuts or something?"

"It isn't going to eat her," Gard said. "It wants the mead for the same reason it wants the girl."

I waited a beat for her to elaborate. She didn't. "I'm rapidly running out of willingness to keep playing along," I told her, "but I'll ask the question-why does it want the girl?"

"Procreation," she said.

"Thank you. Now I get it," I said. "The thing figures she'll need a good set of beer goggles before the deed."

"No," Gard said.

"Oh, right, because the grendelkin isn't human. The thing thing is going to need the beer goggles." is going to need the beer goggles."

"No," Gard said, harder.

"I understand. Just setting the mood, then," I said. "Maybe it picked up some lounge music CDs, too."

"Dresden," Gard growled.

"Everybody needs somebody sometime," I sang-badly.

Gard stopped in her tracks and faced me, her pale blue eyes frozen with glacial rage. Her voice turned harsh. "But not everybody impregnates women with sp.a.w.n that will rip its own way out of its mother's womb, killing her in the process."

See, another answer. It was harsher than I would have preferred.

I stopped singing and felt sort of insensitive.

"They're solitary," Gard continued in a voice made more terrible for its uninflected calm. "Most of the time, they abduct a victim, rape her, rip her to shreds, and eat her. This one has more in mind. There's something in mead that makes the grendelkin fertile. It's going to impregnate her. Create another of its kind."

A thought occurred to me. "That's what kind of person still has her instructions taped to her birth control medication. Someone who's never taken it until very recently."

"She's a virgin," Gard confirmed. "Grendelkin need virgins to reproduce."

"Kind of a scarce commodity these days," I said.

Gard snapped out a bitter bark of laughter. "Take it from me, Dresden. Teenagers have always been teenagers. Hormone-ridden, curious, and generally ignorant of the consequences of their actions. There's never been a glut on the virgin market. Not in Victorian times, not during the Renaissance, not at Hastings, and not now. But even if they were ten times as rare in the modern age, there would still be more virgins to choose from than at any other point in history." She shook her head. "There are so many many people, now." people, now."

We walked along for several paces.

"Interesting inflection, there," I said. "Speaking about those times as if you'd seen them firsthand. You expect me to believe you're better than a thousand years old?"

"Would it be so incredible?" she asked.

She had me there. Lots of supernatural critters were immortal, or the next-best thing to it. Even mortal wizards could hang around for three or four centuries. On the other hand, I'd rarely run into an immortal who felt so human to my wizard's senses.

I stared at her for a second and then said, "You wear it pretty well, if it's true. I would have guessed you were about thirty."

Her teeth flashed in the dim light. "I believe it's currently considered more polite to guess twenty-nine."

"Me and polite have never been on close terms."

Gard nodded. "I like that about you. You say what you think. You act. It's rare in this age."

I kept on the trail, quiet for a time, until Mouse stopped in his tracks and made an almost inaudible sound in his chest. I held up a hand, halting. Gard went silent and still.

I knelt down by the dog and whispered, "What is it, boy?"

Mouse stared intently ahead, his nose quivering. Then he paced forward, uncertainly, and pawed at the floor near the wall.

I followed him, light in hand. On the wet stone floor were a few tufts of greyish hair. I chewed my lip and lifted the light to examine the wall. There were long scratches in the stone-not much wider than a thumbnail, but they were deep. You couldn't easily see the bottom of the scratch marks.

Gard came up and peered over my shoulder. Amid the scents of lime and mildew, her perfume, something floral I didn't recognize, was a pleasant distraction. "Something sharp made those," she murmured.

"Yeah," I said, collecting the hairs. "Hold up your ax."

She did. I touched the hairs to the edge of the blade. They curled away from it as they touched it, blackening and shriveling, and adding the scent of burned hair to the mix.

"Wonderful." I sighed.

Gard lifted her eyebrows and glanced at me. "Faeries?"

I nodded. "Malks, almost certainly."

"Malks?"

"Winterfae," I said. "Felines. About the size of a bobcat."

"Nothing steel can't handle, then," she said, rising briskly.

"Yeah," I said. "You could probably handle half a dozen."

She nodded once, brandished the ax, and turned to continue down the tunnel.

"Which is why they tend to run in packs of twenty," I added, a couple of steps later.

Gard stopped and gave me a glare.

"That's called sharing information," I said. I gestured at the wall. "These are territorial markings for the local pack. Malks are stronger than natural animals, quick, almost invisible when they want to be, and their claws are sharper and harder than surgical steel. I once saw a malk shred an aluminum baseball bat to slivers. And if that wasn't enough, they're sentient. Smarter than some people I know."

"Od's bodkin," Gard swore quietly. "Can you handle them?"

"They don't like fire," I said. "But in an enclosed s.p.a.ce like this, I don't like it much, either."

Gard nodded once. "Can we treat with them?" she asked. "Buy pa.s.sage?"

"They'll keep their word, like any fae," I said. "If you can get them to give it in the first place. But think of how cats enjoy hunting, even when they aren't hungry. Think about how they toy with their prey sometimes. Then distill that joyful little killer instinct out of every cat in Chicago and pour it all into one malk. They're to cats what Hannibal Lecter is to people."

"Negotiation isn't an option, then."

I shook my head. "I don't think we have anything to offer them that they'll want more than our screams and meat, no."