The forest was replaced with a sheet of ice that stretched to the horizon. Only one thing jutted out of it: the dome of the US Capitol building.

Overhead, the sun was dim.

Ty exhaled a breath of white steam, and the world disappeared again.

Next, he was standing atop a stack of metal shipping containers on a massive cargo ship. In every direction, ocean spread out around him.

Ahead, a metal object protruded from the sea. Ty recognized it. It was the top of the Eiffel Tower.

The world vanished, and Ty found himself standing in a space station in front of a wide window that looked down on the Earth.

For a moment he was mesmerized by the view. For Ty, going into space had been a lifelong dream. Now he was here—just like that, in the blink of an eye. In the Way Stations they had just transited, he had gotten a very small glimpse of the wonder of the multiverse. Seen and gone in the blink of an eye. Would this Way Station disappear too? Ty hoped not. He wanted to stay here, to drink in the view and explore this place. He realized it then: he was much like the quantum historians. To him, the multiverse was the ultimate frontier, an endless expanse of possibilities in science and history and human potential. And for some, as he had seen on the A21 world, it was also a place of great misery.

Kato glanced around at the metal walls and hatch that led out of the room. The four historians were standing near the large window.

“Won’t the station personnel detect us here?” Kato asked.

The historian’s computerized voice was loud in the space. “This facility has been abandoned for a long time, though the environmental systems still work. This Way Station should be safe for a while.”

The historian turned their helmet downward, toward the Earth, the view reflected in the mirrored visor. “When you first arrived on A21, all of you

made it clear that you wished to go home. You could have gone home at any time. To the exact place you left. And you still can. Right now.”

The historian reached inside a hip pocket on the suit and drew out a quantum radio medallion that was identical to the one on their chest. The historian tossed it to Kato. “All you need to do is dial the sequence you dialed to leave your world: the third symbol, the fourth, seventh, and eighth. This will be the last time you can dial that sequence to go home.”

Kato looked down at the medallion.

“However,” the historian said, “we have an offer to make you. An offer that could save your world from whatever the Covenant is planning. I hope you will stay a little longer, to hear us out.”

For a long moment, no one said a word. Ty finally broke the silence. “We’re still here.”

The quantum historian walked away from the wide window, deeper into the room of the space station. There were benches near the window and couches beyond that. This place must have been some sort of lounge.

The historian turned to them, and the speaker on the suit rang out in the vast room. “With every passing second, the Covenant grows stronger. Their army gets larger. They conquer more worlds. They have an advantage: they have the map of the multiverse we created together, and a lot of data about populated worlds to work from. We know they’re conducting experiments on hundreds of worlds—and advanced operations like the one you stopped on A21. We must stop them. And we need help. We need a team to do exactly what you’ve just done on A21: serve as our quantum agents. To put it simply, we need you to travel across the multiverse and prevent the Covenant from achieving their goals.”

“And why exactly would we do that?” Kato asked. “For your own self-interest,” the historian replied.

“I’ll decide my own self-interest,” Kato shot back. “And before I do that, I want to go home. I want to see my family again.”

“You can. But as we speak, your world is being manipulated by the Covenant. The changes to your timeline have impacted each of your lives. I believe you have some idea of just how different your lives should be. What we offer is simple: a trade. If you help us stop the Covenant on worlds less fortunate than your own—like the A21 world—we will help you repel the Covenant from your world.”

“How would it work?” Ty asked. “We can’t rewrite history. Our lives are already… changed.”

The quantum historian cocked their head, allowing the silence to stretch out.

In that quiet pause, Ty realized the answer to his question. “Wait. The quantum radio doesn’t just broadcast across the universe. It can cross time, can’t it? I thought so. The medallion could take us back.”

“Space and time are simply two sides of the same coin. Your world is on the verge of learning that. What we offer is what you describe: the ability to rewrite the history of your world. To correct the past. To remove the Covenant from your timeline. When those changes are gone, you will be living in your true world, what we call your Looking Glass World. It’s a world that knows about the multiverse—the dangers of it and the promise of it—and celebrates each of your roles in saving it.”

Ty’s mind was racing. Before he could ask one of the twenty million questions running through his head, Kato’s voice rang out in the room.

“Show us.”

Ty, Nora, and Maria turned to him, and Kato pressed on.

“Show us the world you’re offering. Prove it. Prove that it exists, or my answer is no.”

“We expected this request. And have prepared for it. What you see next is a glimpse of your Looking Glass World. It is what’s waiting for each of you at the end of this road.”