“Sounds good.” If Paul’s a physics student at Cambridge, even if I haven’t met him yet, my parents must have. “Have you seen Paul Markov lately?”

My mother sits up straighter. “Have you seen him around?”

“I—uh, no. I haven’t.”

“Oh, sweetheart.” She scoots closer to put her hands on my shoulders. “Are you still upset? I don’t blame you.”

Upset? “I’m fine. Really.”

“You wouldn’t be asking after Paul, if you really were.” Mom sighs. “Your father and I begged for more stringent measures, but the university code is as clear as it is lenient. Technically, he’d broken no university rules. So we couldn’t expel him from the program. I almost wish we hadn’t already canceled the Firebird project, so we could’ve had the satisfaction of tossing him out of that, at least. But other professors are supposed to be working with Paul from now on! They should have kept him out of your way—”

“I didn’t see him! Okay? It’s all right.” It’s beyond weird to see my mother talking about Paul without a trace of affection, or even grudging respect.

What I see in her eyes is pure loathing.

She rubs my shoulder gently. “I promise you, Marguerite—I absolutely promise—Paul will never come near you again. Never.”

Just when I think I’m home safe, the whole world turns upside down again.

28

THIS TIME I GO THROUGH THE BEDROOM LIKE A FORENSICS team scouring a crime scene. Her closet is emptied out across the bed, every pocket in every coat or pair of jeans searched through. Each and every drawer gets inspected. The spines of each book on this Marguerite’s shelf, and the titles of all the ones in her e-reader, are reviewed. I learn a few things about her—she’s confident wearing heels, she shares my mother’s passion for yoga, she’s a bigger fan of the surrealists than I am. But I don’t find the stuff that would tell me what I want to know.

What happened with Paul?

No blog. No journal. I don’t keep those at home either, but why couldn’t this have been another way she’s different from me? The various apps on her phone show me the photos she’s shared, her latest updates; all of it looks much the way it does on my own phone at home, except that, of course, she has lots of dog photos.

When I scroll all the way back to January, I finally see a picture of Paul. In it, he’s sitting on our red sofa, Ringo happily in his lap. Paul looks completely at ease. At home. And now my parents don’t even want to see his face.

Slightly heated by the exertion of ripping up this Marguerite’s bedroom, I push up the sleeves of my sweater. When I do, beneath my thumb I feel the crooked ridge of the scar on my right arm. The scar seems darker now, which I know is my mind playing tricks on me because the ache has returned.

Well, if I can’t find out anything else about this world’s Paul, I can at least learn how to contact him.

A little time on her tablet turns up Paul’s contact information without too much trouble. The university lists his housing and his email address, at least his school account. With a flick of my fingers, I open a window to write to him, then hesitate.

Mom wanted Paul thrown out of Cambridge—the same guy they practically adopted in at least a dozen dimensions. Anytime my parents and Paul have wound up at odds, Paul was the one who drew the line between them.

The fourth and final splinter of my Paul is here, sheathed within the body of this other Paul Markov. No matter what he’s done, or what he’s capable of, I have to face him. We have to be alone.

Until then, I refuse to worry. During my time traveling through the dimensions, I’ve been kidnapped, held at gunpoint, bombed from the air, nearly crushed in a submarine, exposed to the Russian winter until I nearly died of hypothermia, and chased by a torch-bearing mob intent on burning me for witchcraft. Every time, I’ve kept myself together. Every time, I survived.

Whatever happens next, I have to believe I can handle it. For Paul, I will.

The email I send to Paul is simple and direct.

You and I should talk, soon. Are you free tonight? If so, let me know what time, and I’ll drop by your flat.

(At the last minute, I remembered to use “flat” instead of “apartment.”)

It would be easy to spend the next however-long staring at my in-box, hoping every second to see his reply. But that would only drive me crazy, and besides, Mom made spaghetti.

“Susannah keeps insisting we should visit her in London this summer,” Dad says as he covers his plate with more Parmesan than most people could eat in a month.

Mom looks nonplussed. “But we go every summer, at least for one or two of the plays. I think I read that they’re putting on Julius Caesar at the Globe in June.”

My father shakes his head. “Oh, no, she’s having none of our weekend jaunts. Susannah wants us for a fortnight at least.”

More than a weekend sounds like a very long time to stay with Aunt Susannah, let alone two weeks or however long a fortnight is. To judge by the sound my mother makes, she agrees. It’s kind of sweet that my aunt wants us there, though. At home, our relationship is so much more distant, because my dad and his sister are practically scientific proof of just how different two offspring of the same parents can be. I like that we all found a way to get along here.

As I eat, it’s tough to keep my aching fingers tightened around anything as slender as a fork. My mother is watching me, her face falling as she sees me struggle with my utensils. Quickly I change the subject. “I had the strangest dream last night.”

“Oh, really?” Dad raises an eyebrow in mild curiosity. At his feet, Ringo sits, panting, alight with hope that one of us will drop food.

I try to sound casual. “Yeah. In my dream, we all lived in San Francisco, and we looked and acted like ourselves but had these different lives—and then I realized, this wasn’t my dimension. I’d traveled to another dimension with the Firebird, to see how we lived there. It was so weird how I knew the Mom and Dad and Josie I saw there weren’t you guys, but at the same time they kind of were. I felt like I remembered the whole house, the whole neighborhood, everything.”

Mom and Dad give each other a wistful look. “I suppose it might have been like that,” she says, idly twirling her fork in her pasta. “Sometimes I still daydream about it—truly standing within another dimension.”

“It could still happen,” I venture. “Couldn’t it?”

Dad sighs. “No point in going back to it now. The Firebird project might have been our greatest glory, but it could also have been our greatest folly. Better to turn our energies to more productive ends.”

Oh, come on. No way Mom and Dad would give up on their dream just because they thought it was impractical.

At least now I understand why Conley sent the final splinter of Paul here. Since the Firebird technology had been scrapped, there was no chance my parents would figure out what was going on—and no chance they could have used devices of their own to get him back home.

Then my mother says, “Sending information will be so much more useful than sending consciousness.”

I pause, spaghetti slithering off my fork as I hold it above my plate. “How, exactly?”

She looks dubious, and I wonder if I’ve exposed myself; this world’s Marguerite would surely know more about her parents’ current research. Instead, Mom says, “You’re right to insist that I keep explaining myself. If we don’t revisit our first principles, we run the risk of losing our way.”