“That paper is the single most virulent refutation of your book ever printed. And the woman who wrote it almost got to screw you twice. You can open the door now, Jimmy.”

Leyster made no move toward the doorway. “You’re letting me off with a warning. Why didn’t you do that with the Metzgers?”

“The—?”

“Husband-wife team, attempted causal violation,” the security man said quickly. “Captured 2012, convicted in 2022, released in 2030.”

Griffin seized his wrist and stared down at it, hard. “The world is not a fair place, Mr. Leyster.” He looked up again. “We did it the way we did because according to the records, that’s the way we did it. The rules against paradox bind us as tightly as they do you.”

Hilltop Station: Mesozoic era. Cretaceous period. Senonian epoch. Maastrichtian age. 67 My B.C.E.

Griffin went straight from the orientation lecture to the Mesozoic. The phoniness of the thing, the charade of shaking hands with himself in particular, had depressed him. He needed to refuel. So, opting to avoid the snares and responsibilities of booking travel through his office, he took a local forward thirty years, and used his clout to slip into a VIP tour group headed for the deep past.

They emerged from the funnel and out into the rich air and hot sun of the late Cretaceous. Dinosaurs still walked the Earth, though they wouldn’t for long, and shallow seas so moderated the climate that even the poles were free of ice. Not counting Tent City, where the researchers slept, there were only thirty-seven structures in all the world where one could honestly claim to be indoors.

He was home.

His fellow excursionists were the usual mix of predator capitalists, over-affluent politicians, and decorated heroes of genocidal wars, with a North American admiral and her loud wife thrown in for good measure. Griffin disappeared into the group and let it carry him along. He had the gift for being unobtrusive, when he wanted.

Their guide was what the loud American had, in a sarcastic aside, called “your basic science babe,” blond and fetching in khaki shorts, linen blouse, and white cowboy hat. One had to look hard to see that she was actually rather plain. A couple of the gents, smiling secret fantasies at her backside, preferred not to look that hard. Griffin emerged from private thoughts to discover that she was talking.

“…first thing that people ask is ‘Where are the dinosaurs?’ ” She smiled dazzlingly and swept out an arm. “Well, they’re all around you… the birds!”

In his weary state, the group seemed to Griffin like a cheap jack tourist construction made of bamboo, bright paper, and string, with a crank to turn that would jolt the two-dimensional cutout people into a crude semblance of human life. The guide gave the crank a turn and it chuckled, peered about hopefully, lifted a camera and then decided not to shoot.

“Yes, birds are indeed dinosaurs. Technically speaking, they’re derived theropods, and thus they are distantly related to Tyrannosaurus rex, and kissing cousins to the dromaeosaurids. Even the birds back home in the twenty-first century are dinosaurs. But the behavior of Mesozoic birds is strikingly different from that of modern birds, and many have toothed beaks. Oh, look! There’s a Quetzalcoatlus!”

Crank.

Hands lifted to shade eyes, mouths gaped to let oohs and ohs escape, the camera swung up and went whirr. The girl stood smiling and silent until their reactions had played out, then said, “Now, please follow me up to the top of the observation platform.”

Obediently, they shuffled after her, so many celebredons following in the wake of a lithe young nobodysaurus that the least of them could buy and sell by the job lot. Yet such was the power of organizational structure that they meekly did as she directed.

“But when can we see real dinosaurs?” somebody asked.

“We’ll be able to see non-avian dinosaurs through field glasses from the top of the tower,” the guide said pleasantly. “There’s also a photo safari arranged for those of you who want to get up close and personal with the animals.”

Hilltop Station was situated atop a volcanic plug, steep enough on three sides to keep off everything but the swarms of midges and mosquitoes that rose from the southwestern swamps every evening at sundown. The fourth side sloped gently downward to the flood plain, where most of their research took place. From the top of the observation platform, it was possible to see over the rooftops to the horizon in every direction.

“…and if any of you have questions, I’d be only too happy to answer them.”

“What about the theory of evolution?”

Griffin leaned against the rail, savoring the light breeze that pushed back against him. The sky was thronged with birds, semibirds, and pterosaurs: The Mesozoic truly was the first great age of flight. He stared out over the flood plain, with its scattered stands of ancestral sycamore and gum, metasequoia and cypress. Winding rivers shone like silver, dwindling to threads as they reached for the thin blue line along the horizon that was the Western Interior Seaway.

“I beg your pardon?”

“Have they proved the theory of evolution yet?” It was the American wife, of course. “Or is it still just a theory?”

Someone poked Griffin with a pair of binoculars, but he waved them away. He didn’t need optics to know the dinosaurs were there. There would be ankylosaurs browsing on the berry bushes along the river banks, and herds of triceratopses speckling the flowered plains. Anatotitans ambled between copses of dromaeosaur-haunted poplar or stripped the leaves from cycads and dawn beeches. Lambeosaurs foraged in the swamps. There were mangroves along the seashore, where troodons hunted small arboreal mammals, and—invisible from here—deltas at the mouths of the rivers, where edmontosaurs built their communal nests, safe from the land-bound tyrannosaurs.

“A theory,” said the guide, “is the best available explanation, satisfying all known facts, of a phenomenon. Evolution has held up to two hundred years of rigorous questioning, in which scientists have come up with enormous amounts of information supporting it, and not one shred of disproof. In the paleontological community, it is universally accepted as true.”

“But you don’t have a complete record of one of these creatures changing from one thing into another! Why is that?”

“That’s a very good question,” the guide said, though Griffin knew that it was anything but. “And to answer it, I’ll have to teach you a German word, lagerstatten. That’s quite a mouthful, isn’t it? It means ‘mother lode.’ ” She had modulated her chirpy delivery into a practiced sincerity that Griffin found almost equally grating.

“Before time travel, we had to rely on the fossil record, which is extraordinarily patchy. So few fossils are formed, and of these so few survive erosion, and of those, so very few are found! But occasionally, paleontologists stumbled upon lagerstatten, fossil deposits of extraordinary richness and completeness. These deposits were like snapshots, giving us a very good idea of what life was like for an extremely brief period of time. But a find like the Solnhofen limestone or the Burgess shale was incredibly rare, and great periods of time were hidden from us.”

“But not now,” the American said.

“So you would think. But there are only a dozen or so stations like this one scattered through the 175 million years of the Mesozoic. So that the stations themselves are essentially lagerstatten—fabulously rich sources of knowledge, separated by gulfs of time so vast that we’ll never fill in all the blank spots, try though we might.”

The American nodded to herself. “So it will never be proved.”