"It was Bob's idea," said Arthur. "One of those faster-cheaper-better things the government's so fond of."

Mike nodded. "Reggie mentioned this. Ma.s.s, acceleration, momentum, angle of descent. Tons of math in every throw and it's apparent if any of it changes in midair."

"Exactly."

"Gauss field is steady," Olaf told his microphone. "Power is good."

"That ball's gone through the Door more than anything or anyone else," said Arthur. "Throw it back and forth with Bob a few times."

"Yeah, c'mon, Dad," Bob said from the flatscreen. "Let's have us a catch before you go to work."

Mike smiled. "So," he asked, "whatever happened to all the test animals?"

Arthur blinked and Olaf looked up from his console. On the flatscreen, Bob's smile cracked and he glanced back at Sasha. "What?"

"All the animals that went through the Door. Two hundred and sixteen rats, six cats, and a chimpanzee, yes?"

"Something like that," said Arthur. "Why do you ask?"

"Just curious."

They all looked at Mike.

"A third of the rats were dissected to check for any structural or anatomical issues," Arthur said. "A third of the others were kept under observation for three months each before dissection. The remainder were allowed to live out their lives. None of them ever showed any signs of damage, even on a cellular level."

"Who did the observations?"

"Graduate students at San Diego State. Double-blind observations. They knew nothing about the Albuquerque Door."

"Statistically," said Olaf, "the Door rats had lower cancer rates than the control group."

"Not notably," said Arthur. "It could've been a fluke. The cats went to a shelter after six months of observation."

"I found homes for three of them," Bob said. "People I knew, so we could check on them, if we ever needed to."

"Ready in three."

Mike glanced up at the booth. "Is Glitch one of them?"

"No." Olaf, Neil, and Bob all answered, but the speakers let Jamie's voice dominate. They glanced at one another.

The hoses from the tanks hissed and frosted over. The temperature in the big room dropped by a few degrees. Mike wasn't sure it was from the liquid nitrogen.

"And the chimpanzee?" he asked.

"Six months of observation," said Olaf. "And then Magnus had him sent to a farm up north."

Mike blinked.

"No, really," said Neil, leaning back in his chair. "There's a big wildlife farm for retired movie animals and some test animals up by Los Angeles. I've gone up to see Caesar twice."

"Caesar?"

On the flatscreen, Bob smiled. "What else do you name a chimpanzee who changes the world?"

Olaf sent a stare at Mike. The temperature went down a few more degrees. "If that's all, we're trying to run an experiment."

"Sorry. Didn't mean to distract you."

"Ready in two."

"No worries," said Sasha from the screen. "Everyone gets a little nervous first time they're near it."

Bob waved at Mike. "You still want to throw the baseball?"

"Yep."

"They don't talk about this part," said Bob, "but I think there's something very soothing about tossing a ball back and forth. I call it the Hitchc.o.c.k Effect. I think it helps the brain cope with the idea of a fold in s.p.a.ce, on a psychological level. That's my opinion, anyway."

"You're not a psychologist," said Olaf. "Your opinion's worthless."

"Olaf's jealous because the effect won't be named after him," Bob said.

"Bob," Olaf said without looking at the flatscreen, "how long has it been since I asked you to shut up?"

"A few hours, at least."

"That explains why it's worn off."

Mike tossed the ball from hand to hand and took a few steps toward the mouth. The air around the rings seemed to waver and twist. Even though the room was cool, it still looked like heat haze. The rear wall blurred. It was still clear at the center of the rings, but the ripples were spreading inward.

"We've got a solution," boomed Jamie. "Ready in one."

"Mike," called Neil, "watch the line."

He glanced down at the white lines. "Am I safe here?"

"You can be standing up on the pathway when it opens, if you like. Just don't cross the line."

The circle of still air inside the ring shrunk more and more. Mike estimated it was two feet across at the most. Then eighteen inches. Then less than a foot. The faint hiss of carbonation began to grow. He couldn't tell where it was coming from.

"Power is good," said Olaf. "Flux density is at full. Opening the Door." He tapped three b.u.t.tons and the rings sparked and shimmered.

One moment the heat-haze view through the mouth was the back wall of the main floor, about twenty feet past the second ring. It was cinder blocks with at least two coats of white paint. He could see a few conduits running high along the wall and a fire extinguisher hanging on a square hook.

Then, like a television switching channels, a third ring appeared and Bob stood ten feet away, grinning. The pathway stretched back beneath his feet to another ramp. The wall behind him was almost fifty feet away, and now it was sky blue. Equipment and desks filled the s.p.a.ce between them. Sasha sat at one of them, checking her own instruments.

"Field has cohesion," said Jamie. "The Door is open."

Bob waved to them from Site B. "Hey."

Mike glanced down at the white lines, then leaned to the left.

"Careful," said Neil.

"I see them." Just past the rings Mike could see the rear wall of the building, right where it was supposed to be. He looked the other way, through the metal and ceramic rings, and saw the wall of Site B twice as distant. "It's amazing."

"Yes it is," said Arthur.

"Hey, rookie," Bob said, smiling. He held up his hands and flexed his fingers. "This is the big leagues now. Show me what you got."

Mike looked at the ball in his hand. "Just toss it?"

"Yep."

He lobbed it through the rings. His eyes followed it through the air, watching for a waver to show him when it went through the Door. He couldn't see anything.

Bob caught the ball with both hands. "Not bad," he said. "Try this one." He lifted the baseball for an overhand throw.

Mike studied its path through the air again. He waited for a glitch, for the arc to shift, for something to happen. Nothing did. The ball bounced off his fingertips and rolled across the floor.

Arthur and Bob chuckled. Olaf smirked. Neil scooped up the baseball and tossed it back to Mike.

"Don't overthink it," said Bob. "It's just throwing a ball."

Mike sent the ball through the rings again. Bob plucked it out of the air and threw it straight back. Mike caught it. It was just like catching a ball tossed across the room. A ball tossed a dozen feet at most. He lobbed it through again, and it slapped against Bob's palm.

"Now you're thinking with portals," Bob said with a grin. "For the record, this ball's going sixteen hundred feet every time we toss it. That's about fifteen miles a minute, so you're pitching a nine-hundred-mile-per-hour fastball."

"What's the world record?" asked Mike. He tried an underhand pitch and watched Bob catch it. Still nothing.

"Depends on how they measure it," said Neil. "Nolan Ryan hit a hundred and eight back in the seventies, but most people say Chapman's hundred and five is more accurate, so he's got the current record."

"Only until we go public," said Bob. He tossed the baseball back to Mike.

"We have thirty-five seconds left," Jamie said from the booth.

"Copy that," said Bob. He gestured to Mike and cupped his hands to catch the last throw. He raised his head as the ball smacked into his hand. "For the record, this is now my eighty-fourth time through the Door. That means half of all the crosswalks made by human beings have been made by me, if you round up. I am guaranteed a place in every history book on Earth."

"Are you coming through?" said Olaf. "If not, I'd like to close the Door so I don't have to listen to you."

"That's your jealousy talking again," said Bob as Mike glanced back at Olaf. "It really-"

Olaf's face shifted. Neil screamed. So did Sasha. And Arthur. Mike spun back to the rings, b.u.mped into the other man on the walkway, and stepped back in surprise. He didn't compensate for the ramp and his foot found empty air. He fell back on his a.s.s and slid to the floor, and the figure on the walkway stepped forward to loom over him.

TWENTY.

Mike's first thought was that Bob had rolled his eyes up to show the whites. Students did it in the hall or in cla.s.s as a joke, sometimes with groaning voices or zombie moans. It was hard to do for more than a few seconds.

He could see Bob's irises because his eyes were wide open, not half-lidded. They were pale and lifeless. The pupil of the left eye was a cloudy blur. The right eye looked around the room. It stared at Mike and dilated wide open. He'd seen the same look from terrified animals.

Bob's skin was yellow, the color of Post-it notes or old pencils. His mouth was a chapped, cracked gash. Half of his nose was gone, and the nostril left behind was a slit at the center of the face. A few patches of red stubble were all that remained of his hair.

Nothing was left of his clothes but rags. His left arm had been twisted into a knot of muscle and bruised flesh. It hung from the shoulder in an odd way. The hand at the end was blurred by a collection of scars. Glistening trails led up his yellow body to open sores.

His left side was soaked with blood. The ragged shirt and pants were almost stained black with it. The mutilated arm was pressed against his torso, covering a wound. Drops of blood splashed against the pathway or pa.s.sed through the expanded steel to the concrete.

Bob let out a low moan. It stretched out and mixed with Arthur's scream. Sasha yelled something on the other side of the Door. The ants ran it back in Mike's mind three times before he combined the sounds with some basic lip-reading.

Not again!

"Call nine-one-one," shouted Neil. "Somebody call nine-one-one!"

Bob wailed again. The awful sound echoed through the concrete room. He took a few strides down the ramp as he gazed around the chamber.

Mike kicked against the floor and pushed himself away from the scarred man.

Bob lumbered after him. Every step threw him off balance and almost toppled him. His good arm swung up as he staggered forward.

Alarms bleated. Mike looked over and saw Olaf's hand pressed against the panic b.u.t.ton. There was a deep thump, a shockwave that rippled through the air as the Door slammed shut and Sasha vanished from sight.

The thing that had been Bob turned its good eye to Mike. The bleached iris shrunk, tried to focus, and relaxed. His knees folded and the yellow man collapsed. He dropped down onto his knees, then tilted back. His skull cracked against the steel ramp. More blood poured out onto the floor.

Arthur stopped screaming. He stood with his hands at his mouth. His eyes went from Bob to the rings and back.

"First aid kit!" bellowed Olaf. He ran to Bob. Neil lunged for the white box mounted behind one of the workstations and ripped it from its bracket.

Bob twitched on the floor. His limbs thrashed, went still, and thrashed again. He took a few quick, rasping breaths. Mike and Olaf tried to hold him steady.

"Jesus, that's a lot of blood," Neil said.

"It's a head wound," said Mike. "Head wounds bleed a lot. It's probably not that bad."

Neil pulled a handful of gauze pads from the first aid kit, tore them open and shoved them at Olaf. They lifted Bob and placed the pads behind his head. They turned red. Olaf applied pressure. Bob opened his mouth wide and hissed.

Mike counted seven sockets where teeth had been just a minute ago.

Neil stared at Bob's arm. "What happened to his skin?"

"It's just the light," said Olaf, glancing at his own tanned fingers.