NIGHT HAD FALLEN on London's Baker Street. The orange glow of the streetlamps reflected off pavement that seemed perpetually wet. A good number of pedestrians still walked the sidewalks, mostly heading home from the cafe's. Teamtime had barely passed, and in London, tea was more than just hot drinks.

A little south of regent's park and a little north of the Baker Street Tube station-near 221B-one particular pedestria opened his palm and let an etched gold cube drop to the ground.He kept on walking.No one shouted after the man to tell him he had dropped something.No one noticed at all.

The cube clinked and clacked like a metal die, only not quite the same, thanks to tiny gems at each of the eight corners. It paused once. It paused once, balancing on a single jewel for an unnatural space of time, then rolled on for another meter or so before coming to a complete stop. There it sat in the grime, glittering and anonymous, as a group of twety-somethings strolled by. Their scraves and their laughing faces were reflected in a darkened shop window, amid lettering that read LOST PROPERTY OFFICE.

Once the laughing pedestrians were safely past, the cube shook and bobbled. Its sides slit open, unfolding into eight spider pushed itself up. It lifted a bulbous glass abdomen filed with sickly green syrup and the skittered across the roof, spirale its way up a steaming vent pipe, and disappeared inside.

The creature descended for what seemed like ages, spiked feet clicking all the way. It took several branches, making lefts and rights into joining pipes, but always it continued downward,deep into a massive, secret underground tower know as the keep.

Finally, the spider came within view of a blazing fire and slowed. It crept, inch by inch, to the underside of a great mahogany hearth, training its tiny cameras on a pair of children seated in high-backed velvet chairs in an otherwise dark room. The boy, a teenager, sat staring ito the blaze. The girl,younger,her tiy form dwafed by the victorian chair, gazed at him with an expression of concern. After a moment, the boy stood to inspect the hearth, and the spider scrambled back out of sight.

Then again, there might never have been a spider in the first place. Maybe the gold flashes the boy saw I his mind's eye had nothing to do with a metal cube or tiny gems clacking on pavement. Maybe the silvery spikes had not been the clickety-clicks of a clockswork spider skittering down a pipe. Maybe the boy had imagined the whole thing.

Jack buckles, a tracker by birth, had been struggling with his unsually keen seses. A year before, he had defeated a grown man in a smoky bell tower using only sound and feel to guide his actions. But these days, even the noisy Quantum Electrodynamic Drones-better known as QEDS- that hummed around the Ministry of Trackers could sneak up on him. Jack's senses had been failing him for months.

Ofcourse, o the off chance Jack's sense's had been correct, if a clockwork spider had really crawled down into the keep to look for him, then that would be very, very bad.

JACK RETURNED TO HIS CHAIR, Keeping his eyes the fireplace. He could feel the weight of the inverted underground tower above him, with its black stone walls and unedig levels filled with wood-aneled corridors. The kee had become his prison. The ministry of trackers, the youngest of England's secretive Elder Ministries-behind the Ministry of guilds, the Ministry of Secrets,and the ministry of dragons-had become home for his whole family, whether they liked it or not.

   "You don't look so good", said Sadie, watching as he eased himselfdown in the chair again.

  "I'm nervous. that's all."

   Sadie pulled her ankles u ito a cross-legged position beneath her dress and leaned her elbows on her knees, auburn hair flopping forward. She stared at jack as if she could see right through his skull and into his messed-up tracker brain.

"No. That's not it.

   Jack shot her a frown. "I've asked you not to do that."

   "yes."Jack did not stir.

   Sadie seemed unperturbed by contradiction between his answer and his actions. Her face remained as placid as ever. "Is the professor coming?" she asked, referring to Edward Tanner, the only remaining tracker of the eleventh generation. He want know as the professor simply because he was Jack's teacher and mentor. Long retired from the usual ministry work, the elderly tracker now maintained tenure as a history professor up at Cambridge.

"He's molding young minds tonight."

"What about Gwen?"

jack had known that question was coming. He sighed. "I don't think so."

''because shes mad at you?''

''No.''

''Because you're working with Ash now?''

''No.'' he gave a little shrug. ''Maybe.''

''Because Ash is a journey man quartermaster, ad Gwen is only a clerk?''

jack said nothing.

''But you're only a clerk.''

''Sadie.'' he have her a that's-enough glare and the room fell silent for several seconds. It never did.

''Soooo, why cant she go with you?''

jack rubbed his head. It hurt.Gwen hadn't shown up to see him off-twice in a row now. It wasn't his fault he couldn't study with her everyday,or eat with her, or do whatever Gwen wanted to do whenever Gwen wanted to do it. His dad needed him. couldn't she see that?

Jack slipped a hand into the pocket of his dad's leather jacket, the one he had taken as his own when he first found the armory and equipment locker in his dad's study. He wrapped his palm around a little red sphere with gold lattice-wrk, letting the silky pink coolness of the stone seep into his fingers. Feelings, sounds, smells-the all had a color adnd texture to him, a side effect to his crisscrossed tracker senses.

He closed hi eyes and released a long breath throughhisnose. That same sphere had given him a brief connection to his dad the year before, on the night he had rescued him and confronted the Clockmaker at the top of Big Ben. On his return to the keep, jack had found a tiny scrap of packing paper folded up o the sphere's place in the armory, marked with a curvy Z. So he had name d it zed. After that night, no matter how hard he tried, he had never been able to produced the connection with his dad. He kept the zed with him at all times anyway. It calmed him, helped him think ,helped him b the tracker everyone expected him to be. He couldn't say why. Maybe it gave him power. Maybe it gave him a little bit of his dad's tracker mojo. There were stranger artifacts with stranger abilities everywhere within the keep.

The pain Jack's head subsided, and he realized Sadie was standing over him. With the zed to settle him, he could see without opening his eyes-by the blue-gray whisper of her breathing and the tan, sandpapery shuffle of her feet. He looked up anyway, because he wanted her to see the annoyance in his expression.''what, Sadie?''

''they're waiting for you.'' she glanced over at the big shadowed door.''All of them.''

it was Sadie who finally opened the mahogany door, leaning her little body back into the pull, with jack standing reluctantly behind her. He wicked as a thrummingwhite light assaulted his QEDs, and a black murmur of whispers. It was noise, all of it. But jack cold still make out some of the words.

Tracker.

Section thirteen.

Freak.

Didn't they know he could hear them?

Jack left his sister in thelittle room and walked out onto a cobblestone lane. There were quiant cottage facades on either side. French, maybe. He couldn't tell yet. He crossed over to a broad semicircular platform set between to houses, and stepped up to a bronze rail to get a better look at what he was up against. Below him, level after level of arching bridges, step stairways, and narrow streets were interwoven to form a village stacked upon itself. English, he thought, scanning the flats and storefronts thant formed the circular periphery of every level. definitely English.what else? Every home ad store on the periphery was a mere facade-elaborate set dressings-but the eyes in the windows wer real enough.

Section thirteen.

Freak.

He Shook his head, pushing back a creeping pain that shouldn't have been there-not after a year of training. Gray mist swirled in the light above him and I the daarkness of the bottom below. The arena was so huge that it had its own weather system,gathering moisture in its upper and lower extremes. Sometimes, according to Gwen at least, it rained. jack had never seen it. Then again, this was only his second time to enter the crucible. The bronze hum rolling across his brain intensified and two quad-style QEDs descended out of the clouds. ble light glowed within round egie housings. Their cameras shifts to keep him in focus. Mrs. Hudson's voice, stern and cold, echoed from a unseen loudspeaker.

''Attention. The tracer has entered the arena. The hunt is on.''

THE CLOCK WAS TICKING.

   Jack and his quartermaster had thirty minutes to identify a stolen artifact, track t down within the arena maze, and steal it back again, out from under the Wardens' big noses. This was the second round of the hunt-the pinnacle of the Trackers Games. It all came back from the ministry regulations, volume one, section six, rule nineteen. Competition breeds excellence.

   Four groups comprised the agents of the ministry. Trackers like jack were the firstborn sons of the four founding lines,the only agents to manifest the unique, hereditary tracker Sherlocks, well trained in a host of skills and knowledge that came in handy in the field. Wardens guarded the artifacts, ad sometimes the people, that the Trackers and quartermasters recovered on behalf of the crown. And clerks pushed paper, managed offices, and generally kept the entire house of cards from falling. All of them, from the lowest apprentice clerk all the way up to the Ministry of Trackers, whose identity remained a closely guarded secret, came together each December for the Trackers Games.

   This year's game were Jack's first.

    There had been other events like warden wrestling, cane fencing, and the apprentice clerk deduction challenge, but the hunt was the centerpiece-three rounds of that Gwen liked to call one sided game of catue the flag. Tradition-ally a tracker/quartermaster pair went up against a team of four wardens. The wardens stole an artifact and hid it somewhere within the multilevel labyrinth, and the tracker and his quartermaster had to get it back. Three rounds on three succesive nights, best two out of three, and the Tracker Cup was the prize.

   The wardens had claimed it every year for the last decade.

   Thanks to Section Thirteen, no tracker had set foot in the arena for ten years, leaving the quartermasters to fend for them selves. The infamous regulation protected the ministry from the phenomenon of bad luck and the damage it might do when combined with the considerable abilities of a full-fledged tracker. Each of the four members of the thirteenth genertion-jacks generation-had been exiled to the corners of the earth. At that time, the twelves came back to the keep for the occational mission, but mostly they lived the fourteens,to teach them the sills they had not been permitted to teach their own sons.

   But jack had thrown a wrench into the whole plan. He had stumbled-or rather he had been shoved-back into ministry affairs.

   early a year before,a french psychopath calling himself a clockmaker had kidnapped Jack's father and treatend to burn London to the ground, forcing jack to uncover his hidden past. After jack had stopped the madman, the ministry of trackers had grudgingly opted the to train him. He knew too much. His abilities had manifested early. Jack was dangerous, and sending him out into the wild unchecked was simply not an option. Now, against what many-icluding jack-cosidered better judgement,someone had opted to throw him into the hunt as well.''Where've you been?'' Ashley Pendleton pushed off from a stoe facade not far from the mahogany door, leaning on a wolf's-head cane as he stepped down to the cobble-stones. There was nothing wrong with his legs. Canes were a sign of accomplishment among trackers and quartermasters, and at seventeen ash was the eldest and most accomplished of a journeyman quartermasters.he gave jack a conspirator's wink. ''I was begining to think the old had changed her mind.''

  ''She can hear us, you know,'' said jack, glancing up at the drones.

   Ash scrunched his nose. ''She does't mind.''

   ''Maybe for you.''

    If jack was the embarrassing son of the ministry of trackers kept hidden in the dark, Ash was their poster child-tall and dashing, with a flawless black coplexio and a wining smile. Girls swooned when he passed. Boys fell into step behind him. Only ash with his undeniable charm could get away with referring to Mrs. Hudson-the ultimate clerk,the matron of the ministry-as the old girl. And only ash could have convinced her to allow jack to compete beside him.

   The quartermaster wrapped an arm around Jack's shoulders and hurried him along the curving lane. ''Don't look so worried. No one's ever been killed In the hunt.'' he grinned, tipping up his newsboy cap with the tip of his cane. ''severely wounded, sure, but ever killed. we've taken the first round, jack. Trackers and quartermasterss, together again. One more quick win and the cup will finally return to its proper place.''

   ''Right.Quick.'' jack let out a nervous chuckle. They had won the previous round, when the area maze had been a wharf district straight out of duckens, but there had been next to useless. He didn't see this round going any better.

   They passed beneath a wrought-iron arch into a small cemetery, the starting point for the nights maze. Something there would be missing-something unexpected.Ash paused at the edge of the gravestones and stooped down to Jack's height. ''listen, I know you're nervous. Years ago, there would have been four trackers to choose from, and the oldest or the best would have represented our team in the hunt. But right now, you're all we've got.''

   ''you call that a pep talk?"

'''you didn't let me finish. I don't care that you're young,