I knew Theo lived in Paris; I hadn’t forgotten the letters he sent me while I was in St. Petersburg, talking about the Moulin Rouge. But it hadn’t occurred to me to look Theo up, mostly because I can’t figure out how they would know each other. It’s not like our Russiaverse selves have anything in common. Theo is a leading student of chemistry; I’m a member of royalty from the other side of the continent.

Together we fight crime, I think, and my own stupid joke makes me silly. I muffle my laugh with my lace handkerchief, trying to make it sound like a cough.

“Your Imperial Highness?” Theo asks as the waiters step out of the room, closing the doors behind them. Though my security detail waits just outside, for now Theo and I are alone. “Are you well?”

“Very well, thank you.” How do I put this? “I’m just—I’ve been absentminded lately, and I completely forgot what you and I had intended to talk about—”

His eyes widen. “The amnesia has affected you again?”

“Amnesia?”

Theo nods, like he knows he needs to take this slowly. His voice is patient as he says, “The malady overtook me in December. It was during this time I wrote to you, forging our acquaintance. You contacted me in January with your intriguing ideas about our other selves who knew one another, the shadow worlds—”

She remembered everything. “Shadow worlds,” I repeat.

“If your theory is correct,” Theo says, “it was my shadow-self who inhabited my body last December, acting in my stead. Do you remember none of this?”

Then he sits up straighter, his smile fading. He’s guessed the truth, now; the only way to keep his trust is to admit it.

“As a matter of fact, I’m from one of the—shadow worlds,” I say. “I don’t mean any harm, to the grand duchess or you or anyone.”

Besides Wyatt Conley. But he doesn’t count.

Theo doesn’t know what to make of that, and no wonder. After a moment he says, “Can you explain the scientific principles at work?”

As in my universe, he’s a hipster on the outside, pure science geek on the inside. “Not very well. But I’ll try.” I don’t know what else to say. “Why did the grand duchess contact you?”

“To see if my impressions of December’s events matched her own. She did not share my total amnesia, but as outlandish as her explanation was, I came to believe it.”

In other words, she had to check to make sure she was sane. The letters I exchanged with Theo last December were the only proof she had that the shadow worlds were more than a delusion.

Amazement has animated Theo, turned him into a guy closer to one I know. “Do you perhaps have one of those miraculous devices?”

“A Firebird.” I snag my finger under the chain. It takes him a moment to focus on material from another dimension, but his expression lights up when he does. I add, “If you ever need to check whether someone is native to this dimension, you can look for a Firebird. They’ll almost certainly have it on.”

I tug at his collar, as an example of how to check, but to my shock, I see another Firebird chain.

“Your Imperial Highness?” Theo says, still unaware anything is hanging around his neck.

I snatch up his Firebird, hit the reminder sequence, and—

“Owwww!” Theo pushes back, grabs his chest, and then looks around at our opulent surroundings. “Whoa. Okay, I don’t know where we are, but I like it.”

“What are you doing here?” I demand. “Did you already talk to Conley?”

“Hello to you, too.” When I give him a look, he sighs. “No, I didn’t go to the coordinates you gave me. Instead, I followed you.”

“We were supposed to go to him after we were done!”

“Which we will. He never said we couldn’t take a short detour first.”

Frustration tightens my fist around the lace handkerchief I’m still clutching. “What if Conley thinks we’re skipping out on him? He could splinter Paul into another four pieces—” Or four dozen. Or four million, so I’d never get him back again.

“Hey,” Theo says sharply. “You’re the one Conley’s after. This train doesn’t move forward unless you’re aboard. Besides, as far as Conley knows, we’ve been good little soldiers so far. He’s not going to break the deal yet.”

He doesn’t know that any more than I do. Still, I sense he’s right—for now. Conley won’t put up with a delay for long. “You understand why I came to this dimension, right?”

Theo nods, but his smile fades. “Yeah, I know. You needed to get your head together. What happened in New York—that was intense.”

“More for you than for me,” I say.

“We can save the Most Traumatized competition for later, all right? Okay, you wanted to rest someplace—luxurious, I guess, someplace where you knew you’d be safe.”

“You think I came here because it was ‘luxurious’?”

Theo holds out his hands in a way that takes in the crystal chandelier above us, the painted murals on the walls, all of it, like, Am I wrong? But he adds, “And you needed to be safe. Right? Otherwise it has to be sad for you, remembering—you know. The other Paul.”

He honestly doesn’t get it. “Theo, I came to this dimension because it’s the only one where I knew I wouldn’t see Paul. I couldn’t even look at him, not after what he did to you.”

Theo winces; he covers one knee with his hand. “That sucked beyond the telling of it. But it’s not like our Paul shot me.”

“The different versions—they’re more alike than unalike. Don’t you see that?”

“What, so, if one Paul did something crappy to me, I should hate every version of Paul from then on?”

“That’s not what I meant.”

The flickering gas lamps on the walls no longer seem to shed enough light. Instead of appearing luxurious, the heavy wood carving and enormous overhead chandelier begin to make me feel claustrophobic. A gilded cage is still a cage.

Slowly I say, “Theo, the first time I came to this world—this is where I began to believe that no matter how different we are in each dimension, something within us is always the same. Call it an eternal soul, or a spirit, but whatever it is, it’s the most important thing about us, and that’s the constant. That’s the part that never changes, no matter what.”

“The soul,” Theo says, in a tone of voice I’ve heard my whole life from my parents and every single one of their grad students; it means, This is not science.

Sometimes they think nothing but hard, empirical fact matters.

Which is total crap.

“Yes,” I shoot back. “The soul. And I thought I knew Paul’s soul even better than I knew my own. But when he shot you, I realized there were ways I don’t know him at all. I’ve seen darkness inside him. True darkness. And I still love him, which is scarier than anything else. But I don’t know what to think or what to do—”

My throat closes up, and I blink back tears. Pregnancy hormones, I think.

Theo doesn’t even know about the baby yet.

I look up at him for comfort, then pull back, because at this moment Theo is furious.