Louise Benoit heard the sound of the opening door; someone was coming out onto the deck above the detector chamber. “Yoo-hoo!” she called, getting Dr. Montego’s attention. “Over here!”

Reuben Montego, a Jamaican-Canadian in his mid-thirties, hurried over to them. He shaved his head completely bald—meaning he was the only person allowed into SNO without a hair net—but, like everyone else, he still had to wear a hardhat. The doctor crouched down, rotated the injured man’s left wrist, and—

“What the heck is that?” said Reuben, in his accented voice.

Louise saw it, too: something set, apparently, into the skin of the man’s wrist, a high-contrast, matte-finish rectangular screen about eight centimeters long and two across. It was displaying a string of symbols, the leftmost of which was changing about once per second. Six small beads, each a different color, formed a line beneath the display, and something—maybe a lens—was positioned at the end of the device farthest up the man’s arm.

“Some kind of fancy watch?” said Louise.

Reuben clearly decided to ignore this mystery for the moment; he placed his index and middle fingers over the man’s radial artery. “He’s got a decent pulse,” he announced. He then lightly slapped one of the man’s cheeks, then the other, seeing if he could bring him to consciousness. “Come on,” he said in an encouraging tone. “Come on. Wake up.”

At last the man did stir. He coughed violently, and more water spilled from his mouth. Then his eyes fluttered open. His irises were an arresting golden brown, unlike any Louise had ever seen before. It seemed to take a second or two for them to focus, then they went wide. The man looked absolutely astonished by the sight of Reuben. He turned his head and saw Louise and Paul, and his expression continued to be one of shock. He moved a bit, as if trying perhaps to get away from them.

“Who are you?” asked Louise.

The man looked at her blankly.

“Who are you?” Louise repeated. “What were you trying to do?”

“Dar,” said the man, his deep voice rising as if asking a question.

“I need to get him to the hospital,” said Reuben. “He obviously took a nasty hit to the head; we’ll need skull x-rays.”

The man was looking around the metal deck, as if he couldn’t believe what he was seeing. “Dar barta dulb tinta?” he said. “Dar hoolb ka tapar?”

“What language is that?” Paul asked Louise.

Louise shrugged. “Ojibwa?” she said. There was an Ojibwa reserve not far from the mine.

“No,” Reuben said, shaking his head.

“Monta has palap ko,” said the man.

“We don’t understand you,” said Louise to the stranger. “Do you speak English?” Nothing. “Parlez-vous franсais?” Still nothing.

Paul said “Nihongo ga dekimasu ka?” which Louise assumed meant’, “Do you speak Japanese?”

The man looked at each of them in turn, eyes still wide, but he made no reply.

Reuben rose, then extended a hand down toward the man. He stared at it for a second, then took it in his own, which was huge, with fingers like sausages and an extraordinarily long thumb. He let Reuben pull him to his feet. Reuben then put an arm around the man’s broad back, helping to hold him up. The man must have outweighed Reuben by thirty kilos, all of it muscle. Paul moved to the man’s other side and used an arm to help support the stranger as well. Louise went ahead of the three of them, holding open the door to the control room, which had closed automatically after Reuben had entered.

Inside the control room, Louise put on her safety boots and hardhat, and Paul did the same; the hats had built-in lamps and hearing-protection cups that could be swung down when needed. They also put on safety glasses. Reuben was still wearing his own hardhat. Paul found another one on top of a metal locker and proffered it to the injured man, but before he could respond the doctor waved the hat away. “I don’t want any pressure on his skull until we’ve done those x-rays,” he said. “All right, let’s get him up to the surface. I called for an ambulance on my way over.”

The four of them left the control room, headed down a corridor, and walked into the arrival area for the SNO facility. SNO maintained clean-room conditions—not that it mattered much anymore, Louise thought ruefully. They walked past the vacuuming chamber, a shower stall-like affair that sucked dust and dirt off those entering SNO. Then they passed a row of real shower stalls; everyone had to wash before entering SNO, but that, too, wasn’t necessary on the way out. There was a first-aid station here, and Louise saw Reuben looking briefly at the locker labeled “Stretcher.” But the man was walking well enough, so the doctor motioned for them to continue out into the drift.

They turned on their hardhat lights and began trudging the kilometer and a quarter down the dim dirt-floored tunnel. The rough-hewn walls were peppered with steel rods and covered over with wire mesh; this far beneath Earth’s surface, with the weight of two kilometers of crust pressing down on them, unreinforced rock walls would burst into any open space.

As they walked along the drift, occasionally coming across muddy patches, the man began to take more of his own weight; he was clearly recovering from his ordeal.

Paul and Dr. Montego were engaged in an animated discussion about how this man could have possibly gotten into the sealed chamber. For her part, Louise was lost in thought about the ruined neutrino detector—and what that was going to do to her research funding. Air blew into their faces all the way along the drift; giant fans constantly pumped atmosphere down from the surface.

Finally, they reached the elevator station. Reuben had ordered the lift cage locked off here, on the 6,800-foot level—the mine’s signage predated Canada’s switch to the metric system. It was still waiting for them, no doubt to the chagrin of miners who wanted to come down or go up.

They entered the cage, and Reuben repeatedly activated the buzzer that would let the hoist operator on the surface know it was time to start the winch. The lift shuddered into motion. The cage had no internal lighting, and Reuben, Louise, and Paul had turned off their hardhat lamps rather than blind each other with their glare. The only illumination came in flashes from fixtures in the tunnels they passed every 200 feet, visible through the open front of the cage. In the weird, strobing light, Louise caught repeated glimpses of the strange man’s angular features and his deep-set eyes.

As they went higher and higher, Louise felt her ears pop several times. They soon passed the 4,600-foot level, Louise’s favorite. Inco grew trees there for reforestation projects around Sudbury. The temperature was a constant twenty degrees; adding artificial light turned it into a fabulous greenhouse.

Crazy thoughts occurred to Louise, weird X-Files notions about how the man could have gotten inside the sphere with the trapdoor still bolted shut. But she kept them to herself; if Paul and Reuben were having similar flights of fancy, they were also too embarrassed to give them voice. There had to be a rational explanation, Louise told herself. There had to be.

The cage continued its long ascent, and the man seemed to take stock of himself. His strange clothes were still somewhat wet, although the blowing air in the tunnels had done much to dry them. He tried wringing out his shirt, a few drops falling on the yellow-painted metal floor of the elevator cage. He then used his large hand to brush his wet hair off his forehead revealing, to Louise’s astonishment—she gasped, although the sound surely was inaudible over the clanging of the rising car—a prodigious ridge arching above each eye, like a squashed version of the McDonald’s logo.