Pony almost spit out a mouthful of soda. Nellie was sitting in his chair, but there was something distinctly un-G.o.ddesslike about her.

"You look . . . weird."

"You know, Pony, I think it's your tact that makes everyone love you so much."

"But your hair. And your clothes. You're dressed like my mom."

Nellie's brown eyes narrowed on him. "I'm undercover," she growled. "Now sit down. I need your help."

"What's up?"

"I need anything you can get me on Trilon Laboratories."

This was music to Pony's ears. Nellie moved out of his chair and he leaned into his keyboard like a musician, his fingers be-bopping over the keys, pounding out a crisp plastic rhythm. In the end the whole thing was a bit of a disappointment. Pony shrugged and took another swig of his hacker juice. "There."

"There what?"

"Pwnage. Total and complete pwnage."

"I really need some kind of geek-to-English dictionary."

"I'm in," Pony said. "Right in the middle of their systems. Trilon Laboratories now officially works for me."

"Already?"

"It was just off-the-shelf security stuff. Easy to break."

"So what's there?"

Pony surfed the system, dipping in and out of files at will. "Not much. E-mail. Some accounting stuff. A list of all fifty-seven employees."

"Wait. Fifty-seven? I saw like a hundred people in the parking lot."

Pony surfed around until he could bring up a rough schematic of the building. "In here? They'd need a crowbar to fit that many people in a building this size."

"Can you print that out?"

One keystroke and a full set of blueprints were spooling through the printer. Pony spread them out on a table and pored over lines and notation.

"Anything weird?" Nellie asked.

"It appears to be a building," Pony said. "With walls and a floor. And a roof."

Nellie glared at him.

"What? Paper isn't really my strong suit."

Nellie pushed him out of the way and traced the maze of lines in and out of rooms. She turned a page to look at the electrical wiring schematics.

"Huh," she said. "Look."

Pony sat forward, flipping the pages back and forth. He would never have thought it possible with something as supremely lame as some sheets of paper, but he started to feel that familiar hacking feeling. It was like he was melting into the data, becoming one with it, losing himself. For a flash of a second, Pony was those blueprints.

"Do you see it?" Nellie asked.

"It's like there are two buildings," Pony said. "Look at the bas.e.m.e.nt. The walls and the ceiling are super thick, way heavier than anything else upstairs, like they're blast walls or something. And it's got like an entirely separate electrical system. And look at all of the elevators and staircases."

Nellie stared down at them but shook her head. "I don't see anything."

"They don't actually go down into the bas.e.m.e.nt," he said. "With all the people you said were there, you'd think they'd make sure there were plenty of ways to get downstairs but they don't. The elevator shafts and the stairways all stop at the first floor. Except for this one." Pony pointed out what looked like another stairwell. "That one goes all the way down."

Nellie thought back to wandering the halls on her way to her lab, trying to match her memories with the blue and white lines before her. "I've never seen stairs there."

"No surprise," Pony said. "According to the plans, they lead right up to a solid wall. There's no entrance or exit into that stairwell on any floor but the bas.e.m.e.nt."

"I'm guessing we should put that in the suspicious column," Nellie said as she gathered the plans. "Good work."

Nellie gave him a sisterly sock on the arm and headed out with the plans under her arm. Watching her go, Pony felt that deflated feeling he usually got after disconnecting from a serious day of hacking. It was strange. Pony had always been a loner. A keyboard jockey in a dank bas.e.m.e.nt living on Electroshock and anchovy-and-pineapple pizza. But now he was part of a team.

There's no way I'm letting these people down.

Pony pulled up to his computer and took another slug of Electroshock.

"Time to go to war, Founders Media," he said, cracking his knuckles one by one. "Brace yourself for ultimate pwnage."

Amy's clothes snapped like flags in the wind out on the ledge. She dared a quick look down and instantly regretted it. The concrete sidewalk four stories below seemed to have an almost magnetic pull.

With Jake in the lead, the four of them inched toward a ladder that led to the roof. They kept their backs plastered to the wall, the tips of their toes dangling over the crumbly stone. So far the police down below hadn't noticed them, but they were still pounding away at the hotel room door. It was only a matter of time before they got in.

She took another shuffling step and Atticus faltered beside her, one foot slipping off the edge. Amy threw an arm over his chest, flattening him against the wall. She could feel his heart pounding beneath her fingertips. Amy gave him a weak smile.

"It's okay," she whispered. "Look."

Up ahead, Jake grabbed the ladder and pulled himself onto it. Amy's relief only lasted a second. There was a wooden crash behind her as their hotel room door shattered. The police had made it inside.

"Stop where you are!" a police officer yelled, leaning out the window.

"Go!" Amy said, and pushed Atticus ahead of her. Jake was scrambling up the ladder now and Dan was almost to it.

"You!" the officer shouted. "Down below! Lights!"

Spotlights exploded from the street. Amy held up a hand to block them and saw that Pierce's men had broken from the others and were storming into the hotel.

Dan jumped onto the ladder and pulled Atticus on behind him. With a quick prayer Amy threw herself onto the metal rungs. There was more shouting below them now, and the sound of more vehicles arriving. She was nearly to the top when one hand, greased with sweat, slipped. Gravity dug in and tried to pull her back, but Dan's hand snapped onto her wrist, holding her steady. Amy pulled herself over the edge and onto the dark roof.

"It won't be long before they're up here," Dan said.

Amy scanned the rooftop. There was a doorway in a far corner she figured led to a stairwell back down into the hotel. "We fake them out," Amy said. "Go back down, then -"

"Hey! Over here."

Amy and the others joined Jake. He had crawled his way across the roof and was at the southern edge of the hotel. They were ten stories up now, with all of Tunis stretched out below. It was a densely packed city, one rooftop bleeding into the next, like a series of steps heading straight down to the tangle of the medina.

Jake looked over his shoulder at Dan, who shrugged, then backed away from the edge and dropped into a runner's stance.

"Whoa!" Amy said. "Jake, we can't -"

Two police officers blew through the door on the roof, guns drawn. "You there! Stop where you are!"

Dan broke into a run.

"Dan, no!"

Dan sprinted past her. His right foot hit the top of the stone wall and launched his body into the air, sailing over the three-foot gap to the next building. Amy leaped up to see him hit the rooftop hard and roll away. Jake followed, but Atticus was hanging back, clearly terrified. The police were halfway across the roof. They'd be on them in seconds. Insane or not, it was their only chance. Amy grabbed Atticus's hand and together they raced toward the edge of the roof.

Amy's foot touched the wall and she threw herself as hard as she could into the open air. Atticus did the same, and for a second they were both weightless, hurtling across s.p.a.ce hand in hand.

Amy hit the roof of the opposite building shoulder-first and rolled away. Pain shot through her side but she ignored it, turning back to look for Atticus. He wasn't beside her.

"Atticus!"

The fingers of one small hand grasped the edge of the roof. Amy raced over and grabbed Atticus's wrist, his small body twisting over the concrete below. Amy tried to muscle him over the edge, but his skin was sweaty with fear and he started to slip. She scrambled for a better hold, but he was slipping fast and pulling her along with him.

Then she felt something behind her, a hand grabbing her shirt and pulling. She looked back. Dan. Jake appeared beside her, grasping at Atticus's other arm. Together, the three of them hauled Atticus up and over the edge. He hit the tar paper panting and Jake threw his arms around him.

"You there! Don't move!"

The police were at the edge of the hotel's roof. Jake pulled Atticus to his feet, and a second later they were all up and running. Behind them, Amy heard a cop shout something in Arabic into his radio. Amy grunted as they jumped onto the next roof. Dan landed and then ran beside her, dodging skylights and exhaust columns. He spared a look back. The two cops were still on the hotel's roof.

"Guess they just don't have the skills of the amazing flying Cahills," Dan said.

"Ha!" Atticus said. "Maybe you should try out to be an acrobat instead of a clown."

"Keep going!" Jake said. "There's no way they can keep up with us from down there. We're home free, unless of course they have a -"

The scream of a helicopter's rotors. .h.i.t them a fraction of a second before its searchlight switched on and erased the night around them.

"You are under arrest!"

There was nothing to do but keep running. The four jumped from building to building until the muscles in Amy's legs were screaming. The buildings got lower as they neared the medina. First six stories, then five, then four. But no matter how fast they ran or the clever turns they took, the tight ring of the helicopter's searchlight stayed fixed on them.

"There!" Dan cried.

Dan sprinted for a fire escape and they all followed. They made it down the ladder and dropped into a tight alleyway behind the buildings. The helicopter's beam was still on them, but now it was fractured by full clotheslines and fire escapes and loaded dumpsters. The four kids found a patch of shadow and disappeared into it. The plaza that led into the medina lay straight ahead.

"They have to figure that's where we're headed," Jake said.

"No choice!" Amy said. "Lots of those streets are covered, so it gets us away from the helicopter."

"Is that an order?" Jake asked.

Amy's stomach clenched. "Jake -"

"It's a maze in there, Amy! One they know a lot better than we do. One wrong turn and we end up at a dead end and they've got us."

"No," Dan said. "Amy's right. The medina's the only way."

Amy shot a quick look at her brother. "Can you do it?"

Dan stared out into the night. Amy could feel him engaging that photographic memory of his.

"I don't know," he said. "I think I remember the basic layout but -"

"It'll be enough," Amy said, legs moving like pistons. "You take the lead."

They didn't head straight to the medina. Instead they dodged around in the narrow alleys, until the searchlight slipped off them and the chop of the blades faded.

"Okay," Dan said. "Now!"

They ran out of the alley and toward the square that surrounded the entrance to the medina. They made it into the mouth of the main road and followed it for a few turns. Sirens began to wail out in the square. Amy prayed the vehicles were too big to make it into the cramped streets.

Dan led them on a wild race through unimaginably tangled streets. As they moved deeper into the medina, it was as if he were tying them into knots and untying them over and over again.

Amy heard a metallic radio squawk to her left, and then a pack of bodies moved fast down an adjoining street. Dan pulled them into an alleyway and they crouched behind trash cans as booted footsteps sped up the stone path. Amy held her breath when the boots stopped at the mouth of the alley, her pulse racing. Jake, Atticus, and Dan were hunched down, curled into b.a.l.l.s, trying to make themselves invisible. At their backs was a solid wall of stone. No escape.

Flashlights flared, sending knife-like beacons of light over the piles of trash and debris in the alley. Jake flattened himself just seconds before one of the beams would have illuminated his arm.

The men talked low in Arabic. A radio screeched loudly. Boot heels turned on the gritty road and the men walked back the way they had come.

Amy tried to swallow, but her mouth had gone as dry as the desert. Jake went to stand, but Amy touched his back and he paused. She counted out a long and painful five minutes. When she was done, she peeked her head up cautiously, emerged from her hiding place, and approached the end of the alley.

The helicopter buzzed the tops of the buildings, its searchlight scorching the street in front of her. Once the beam pa.s.sed, Amy steadied herself and moved out onto the street.

She didn't make it two steps before an icy ring of steel pressed into her temple. A deep voice boomed at the opposite end of the black handgun.

"Out of the alley, Amy. Slow."

There was a rustle of movement behind her, but Amy lifted one hand back into the dark to keep the others in their place. Her legs felt heavy and thick, unwilling to move, but she couldn't let Pierce's men come into the alley and see the others. She made herself take a step forward.

Thin moonlight illuminated four men in her peripheral vision. Westerners in black suits, all with the steel-spring bodies of Olympic athletes. The gun barrel at her temple never wavered.

"Where are the others?" the voice beside her asked.

"We split up," Amy said, trying to keep her voice steady. "About a half mile back."

One of Pierce's men ran down the street to check it out.

"What are you kids doing here?" he asked.