an MI6 facility. Maybe she was one of the staff employed in the upkeep of the house, but had no idea what went on here? Surely those people were vetted and supervised, though, and threatened with life imprisonment if they ever set foot outside their prescribed domains.
For one surreal moment, Robert wondered if Quint had sent her to seduce him. It would not have been the strangest thing they’d tried. But she radiated such fierce self-assurance-such a sense of confidence that she could speak with the authority of her convictions, and expect to be heeded-that he knew she could never have been chosen for the role. No one in Her Majesty’s government would consider self-assurance an attractive quality in a woman.
He said, “Throw me the key, and I’ll show you my Roger Bannister impression.”
She shook her head. “You don’t need a key. Those days are over.”
Robert started with fright.There were no bars between them. But the cage couldn’t have vanished before his eyes; she must have removed it while he’d been lost in his reverie. He’d gone through the whole painful exercise of turning to face her as if he were still confined, without even noticing.
Removed it how?
He wiped his eyes, shivering at the dizzying prospect of freedom. “Who are you?” An agent for the Russians, sent to liberate him from his own side? She’d have to be a zealot, then, or strangely naive, to view his torture with such wide-eyed innocence.
She stepped forward, then reached down and took his hand. “Do you think you can walk?” Her grip was firm, and her skin was cool and dry. She was completely unafraid; she might have been a good Samaritan in a public street helping an old man to his feet after a fall-not an intruder helping a threat to national security break out of therapeutic detention, at the risk of being shot on sight.
“I’m not even sure I can stand.” Robert steeled himself; maybe this woman was a trained assassin, but it would be too much to presume that if he cried out in pain and brought guards rushing in, she could still extricate him without raising a sweat. “You haven’t answered my question.”
“My name’s Helen.” She smiled and hoisted him to his feet, looking at once like a compassionate child pulling open the jaws of a hunter’s cruel trap, and a very powerful, very intelligent carnivore contemplating its own strength. “I’ve come to change everything.”
Robert said, “Oh, good.”
Robert found that he could hobble; it was painful and undignified, but at least he didn’t have to be carried. Helen led him through the house; lights showed from some of the rooms, but there were no voices, no footsteps save their own, no signs of life at all. When they reached the tradesmen’s entrance, she unbolted the door, revealing a moonlit garden.
“Did you kill everyone?” he whispered. He’d made far too much noise to have come this far unmolested.
Much as he had reason to despise his captors, mass-murder on his behalf was a lot to take in.
Helen cringed. “What a revolting idea! It’s hard to believe sometimes, how uncivilized you are.”
“You mean the British?”
“All of you!”
“I must say, your accent’s rather good.”
“I watched a lot of cinema,” she explained. “Mostly Ealing comedies. You never know how much that will help, though.”
“Quite.”
They crossed the garden, heading for a wooden gate in the hedge. Since murder was strictly for imperialists, Robert could only assume that she’d managed to drug everyone.
The gate was unlocked. Outside the grounds, a cobbled lane ran past the hedge, leading into forest.
Robert was barefoot, but the stones weren’t cold, and the slight unevenness of the path was welcome, restoring circulation to the soles of his feet.
As they walked, he took stock of his situation. He was out of captivity, thanks entirely to this woman.
Sooner or later he was going to have to confront her agenda.
He said, “I’m not leaving the country.”
Helen murmured assent, as if he’d passed a casual remark about the weather.
“And I’m not going to discuss my work with you.”
“Fine.”
Robert stopped and stared at her. She said, “Put your arm across my shoulders.”
He complied; she was exactly the right height to support him comfortably. He said, “You’re not a Soviet agent, are you?”
Helen was amused. “Is that really what you thought?”
“I’m not all that quick on my feet tonight.”
“No.” They began walking together. Helen said, “There’s a train station about three kilometers away.
You can get cleaned up, rest there until morning, and decide where you want to go.”
“Won’t the station be the first place they’ll look?”
“They won’t be looking anywhere for a while.”
The moon was high above the trees. The two of them could not have made a more conspicuous couple: a sensibly dressed, quite striking young woman, supporting a filthy, ragged tramp. If a villager cycled past, the best they could hope for was being mistaken for an alcoholic father and his martyred daughter.
Martyred, all right: she moved so efficiently, despite the burden, that any onlooker would assume she’d been doing this for years. Robert tried altering his gait slightly, subtly changing the timing of his steps to see if he could make her falter, but Helen adapted instantly. If she knew she was being tested, though, she kept it to herself.
Finally he said, “What did you do with the cage?”
“I time-reversed it.”
Hairs stood up on the back of his neck. Even assuming that she could do such a thing, it wasn’t at all clear to him how that could have stopped the bars from scattering light and interacting with his body. It should merely have turned electrons into positions, and killed them both in a shower of gamma rays.
That conjuring trick wasn’t his most pressing concern, though. “I can only think of three places you might have come from,” he said.
Helen nodded, as if she’d put herself in his shoes and catalogued the possibilities. “Rule out one; the other two are both right.”
She was not from an extrasolar planet. Even if her civilization possessed some means of viewing Ealing comedies from a distance of light years, she was far too sensitive to his specific human concerns.
She was from the future, but not his own.
She was from the future of another Everett branch.
He turned to her. “No paradoxes.”
She smiled, deciphering his shorthand immediately. “That’s right. It’s physically impossible to travel into your own past, unless you’ve made exacting preparations to ensure compatible boundary conditions.
Thatcan be achieved, in a controlled laboratory setting-but in the field it would be like trying to balance ten thousand elephants in an inverted pyramid, while the bottom one rode a unicycle: excruciatingly difficult, and entirely pointless.”
Robert was tongue-tied for several seconds, a horde of questions battling for access to his vocal chords.
“But how do you travel into the past at all?”
“It will take a while to bring you up to speed completely, but if you want the short answer: you’ve already stumbled on one of the clues. I read your paper inPhysical Review, and it’s correct as far as it goes.
Quantum gravity involves four complex dimensions, but the only classical solutions-the only geometries that remain in phase under slight perturbations-have curvature that’s eitherselfdual, oranti-self-dual.
Those are the only stationary points of the action, for the complete Lagrangian. And both solutions appear, from the inside, to contain only four real dimensions.
“It’s meaningless to ask which sector we’re in, but we might as well call it selfdual. In that case, the anti-self- dual solutions have an arrow of time running backward compared to ours.”
“Why?” As he blurted out the question, Robert wondered if he sounded like an impatient child to her.
But if she suddenly vanished back into thin air, he’d have far fewer regrets for making a fool of himself this way than if he’d maintained a fac?ade of sophisticated nonchalance.
