His ears release pressure as they descend.

His stomach tingles with nervous energy.

Glancing over his shoulder, Pilcher stares at Leven in the backseat—a lithe young man with the face of a baby but the eyes of a sage.

“We’re going to be safe breathing in this atmosphere?” Pilcher asks.

“It has altered,” Leven says, “but only slightly. Nitrogen and oxygen, thank God, are still the main components. But the makeup is now one percent more oxygen, one percent less nitrogen. Greenhouse gases have returned to pre–Industrial Age levels.”

“I trust you’ve already begun to depressurize the superstructure?”

“That was the first order of business. We’re already sucking in air from outside.”

“Any other pertinent bits?”

“It’ll be a few days until our systems are fully powered up and debugged.”

“Where does our electron clock place us in terms of the Christian calendar?”

“Today is February 14, 3813, in the year of our Lord.” Leven grins. “Happy Valentine’s Day, all.”

Arnold Pope brings the Humvee to a full stop, its high beams shining against the back side of the titanium portal that has protected the tunnel, the superstructure, and all who sleep within from the world outside.

Pope kills the engine, leaves the lights running.

As they all step out of the truck, Pope walks around to the back and opens the cargo doors.

He takes a pump-action shotgun off the rack.

“For God’s sake, Arnie,” Pilcher says. “Always the pessimist.”

“That’s why you pay me the big bucks, right? If it were up to me, I’d have my entire security team rolling with us.”

“No, we’re keeping this intimate for now.”

Leven says, “Pam, would you mind bringing your flashlight over?”

As she shines the beam onto the release wheel, Pilcher says, “Let’s just wait a beat.”

Leven straightens.

Pope heads over.

Ted and Pam turn to face him.

Pilcher’s voice is still gravelly from the drugs that revived him.

He says, “Let’s not let this moment pass us by.” His people study him. “Do you all understand what we’ve done? We just completed the most dangerous, daring journey in human history. Not across distance. Across time. You know what waits on the other side of this door?”

He lets the question hang.

No one bites.

“Pure discovery.”

“I don’t follow,” Pam says.

“I’ve said it before, I’ll say it again. This is Neil Armstrong going down the steps of Apollo 11 to stand on the moon for the first time. The Wright brothers testing their flyer at Kitty Hawk. Columbus walking ashore into the New World. There’s no telling what lies on the other side of this portal.”

“You predicted that humanity would become extinct,” Pam says.