Mary could feel her heart pounding. “What do you mean?”

“I—it is our way, among our people, not to have secrets between partners, and yet…”

“Yes?”

He turned around and looked back down the drift, making sure they were alone. “There is something I have not told you—something I have not told anyone, except…”

“Except who? Adikor?”

But Ponter shook his head. “No. No, he does not know of this, either. The one person who does know is a male of my kind, a man named Jurard Selgan.”

Mary frowned. “I don’t remember you ever mentioning that name before.”

“I have not,” said Ponter. “He…he is a personality sculptor.”

“A what?” said Mary.

“A—he works with those who wish to modify their…their mental state.”

“You mean a psychiatrist?”

Ponter tipped his head, clearly listening to Hak speak to him through his cochlear implants. The Companion was no doubt breaking the term Mary had presented into its etymological root; ironically, “psyche” was the closest approximation to “soul” the Neanderthals had. At last Ponter nodded. “A comparable specialist, yes.”

Mary’s spine stiffened even as she walked along. “You’ve been seeing a psychiatrist? About my rape?” She’d thought he’d understood, damn it all. Yes, Homo sapiens males were notorious for looking at their spouses differently after they’d been raped, wondering if it had somehow been the woman’s fault, if she’d somehow secretly wanted it—

But Ponter…

Ponter was supposed to understand!

They marched on in silence for a while, their helmet beams lighting the way.

Reflecting on it, Ponter had seemed desperate to know the details of Mary’s rape. At the police station, Ponter had grabbed the sealed evidence bag containing specimens from Qaiser Remtulla’s rape, ripped it open, and inhaled the scent within, identifying one of Mary’s colleagues, Cornelius Ruskin, as the perpetrator.

Mary looked over at Ponter, a dark, hulking form against the rock wall. “It wasn’t my fault,” said Mary.

“What?” said Ponter. “No, I know that.”

“I didn’t want it. I didn’t ask for it.”

“Yes, yes, I do understand that.”

“Then why are you seeing this—this ‘personality sculptor’?”

“I am not seeing him anymore. It is just that—”

Ponter stopped, and Mary looked over. He had his head tilted, listening to Hak, and after a moment, he made the smallest of nods, a signal intended for the Companion, not for her.

“It’s just what? ” said Mary.

“Nothing,” said Ponter. “I am sorry I brought the topic up.”

So am I, thought Mary as they continued on through the darkness.

At last they reached the Sudbury Neutrino Observatory. Ponter and Mary made their way through the massive facility—all hanging pipes and massive tanks—to the control room. It was deserted now; Ponter’s original arrival had destroyed the observatory’s heavy-water detector tank, and the plans to repair it had been put on hold by the subsequent re-establishment of the portal.

They came to the room above the detector chamber, went through the trapdoor, and—this was the terrifying part for Mary—backed down the long ladder to the staging area, six meters off the ground. The staging area was at the end of the Derkers tube, a crush-proof tunnel that had been shoved through the portal from the other side.

Mary stood at the threshold of the Derkers tube and looked into it. The tube was twice as long on the inside as it was on the outside, and at the other end she could see the yellow walls of the quantum-computing chamber over on Ponter’s version of Earth.

A Canadian Forces guard was there, and they presented their passports to him—Ponter had received one when he’d been made a Canadian citizen.

“After you,” said Ponter to Mary, a bit of gallantry he’d picked up in Mary’s world. Mary took a deep breath and walked down the tube, which, when one was inside it, measured sixteen meters long and six wide. Coming to the middle, she could see the ring of ragged blue luminosity through the translucent material of the tube’s wall. She could also see the shadows cast by the crisscrossing metal segments that held the tube open. Taking another deep breath, Mary stepped quickly across the discontinuity marked by the blue ring, feeling static electricity crawling over her body from front to back.

And suddenly she was there —in the Neanderthal world.

Mary turned around without leaving the tube and watched Ponter come toward her. She could see the blond hair on Ponter’s head ruffle as he came through the discontinuity; like most Neanderthals, his natural part was exactly in the middle of his long skull.

Once he was through, Mary turned back around and continued on to the end of the tube.

And there they were, in a world that had diverged from Mary’s own 40,000 years previously. They were inside the quantum-computing chamber she had glimpsed from her side, a vast room filled with a grid of register tanks. The quantum computer, designed by Adikor Huld to run software developed by Ponter Boddit, had been built to factor numbers larger than any that had ever been factored before; piercing into an alternate universe had been entirely accidental.

“Ponter!” said a deep voice.

Mary looked up. Adikor—Ponter’s man-mate—came running down the five steps from the control room onto the computing-chamber floor.

“Adikor!” said Ponter. He ran over to him, and the two men embraced, then licked each other’s faces.

Mary looked away. Of course, normally—if such a word could ever be applied to her existence in this world—she would rarely see Ponter when he was with Adikor; when Two became One, Adikor would hurry off to spend time with his own woman-mate and young son.

But Two were not One, and so here, now, Ponter was supposed to be spending time with his man-mate.

Still, after a few moments, the two males disengaged, and Ponter turned to Mary.

“Adikor, you remember Mare.”

“Of course,” said Adikor, smiling what seemed to be a very genuine foot-wide smile. Mary tried to emulate its sincerity, if not its dimensions. “Hello, Adikor,” she said.

“Mare! It is good to see you!”

“Thank you.”

“But what brings you here? Two is not yet One.”

There it was. A staking of claim; an establishment of turf.

“I know,” said Mary. “I’ve come on an extended visit. I’m here to learn more about Neanderthal genetics.”

“Ah,” said Adikor. “Well, I’m sure Lurt will be able to assist you.”

Mary tilted her head slightly—not that she had a Companion to listen to. Was Adikor just being helpful, or was he making a point of reminding Mary that she would need to seek the assistance of a female Neanderthal, who, of course, would be found in the City Center, far away from Adikor and Ponter.

“I know,” said Mary. “I’m looking forward to talking with her some more.”

Ponter looked at Adikor. “I will take Mary briefly to our home,” he said, “and get her a few things she will need for an extended stay. Then I will arrange her transportation into the Center.”

“Fine,” said Adikor. He looked at Mary, then back at Ponter. “I assume it will be just the two of us for the evening meal?”

“Of course,” said Ponter. “Of course.”

Mary stripped naked—she was losing her self-consciousness about nudity in this world that had never had any religion to impose such taboos—and went through the tuned-laser decontamination process, coherent beams at precise wavelengths passing through her flesh to zap foreign molecules within her body. Already, similar devices were being built in Mary’s world to treat many forms of infection. Sadly, though, since tumors were made of the patient’s own cells, this process couldn’t cure cancers, such as the leukemia that had taken Ponter’s wife, Klast, two years ago.