“IF ONLY GETTING RID OF THE . . . IMPOSTORS SOLVED OUR problems,” Mom said a few minutes later. I was kneeling in front of Paul, who sat on the sofa as I bandaged the gash on his forearm. Dad, meanwhile, was trying to get Theo to drink a cup of tea. (My father is English, so he thinks tea solves everything.) “But based on what you’re telling us—the other two dimensions of Triad are now switching to a new strategy, one far more dangerous than before.”
“They’re willing to destroy entire dimensions, every one that contains a sliver of Josie’s soul,” I said. “Even this one. All to get Josie back. I still can’t believe you guys would ever do that.”
“I can,” my father said quietly. Mom gave him a look, but she folded her arms across her chest, the way she did when she got defensive, as Dad continued. “That bout of meningitis you had when you were two, Marguerite . . . the disease works fast. You were in a pediatric ICU, and the doctors told us we could lose you. The state of mind I was in then . . .” He trailed off, and when he spoke again, his voice was hoarse. “I would’ve made a deal with the devil. Any deal, any devil.”
I remembered my mother’s rage at Paul in a universe where he had only injured me. That alone had been enough to turn all her love for him into hate. My parents pride themselves on being rational, logical people, like the scientists they are, but maybe that’s made them more vulnerable to strong emotion. The same grief that wounds the rest of us deeply is something they can’t even begin to bear. No wonder Josie’s death had driven them mad.
“We have to act immediately.” Paul hadn’t looked me in the eyes since I’d become myself again. His head remained slightly bowed, as though he were too ashamed to lift it. “To do something to protect the dimensions in danger of being destroyed. Triad needs a perfect traveler’s cooperation to accomplish their plan quickly—but even without Marguerite, they have the Triadverse version of Wyatt Conley.”
“It didn’t sound to me like Conley was going to do any of this personally,” I said. Being a perfect traveler could be dangerous, as I’d learned. Conley talked a big game, but he preferred to protect himself and risk others. “And what does ‘slamming doors’ mean? Conley mentioned it, and so did she, but I don’t get what they’re referring to.”
My dad sighed. “Unfortunately, neither do we.”
“Wait a second.” Theo frowned as he stared down at the rainbow table. He lifted his cup of tea from the papers laid across its multicolored surface. “We have some very, very interesting equations here.”
Mom walked to his side. “What do you mean?”
“Not exactly a road map—but maybe a hint to the kinds of places they’re trying to go. The universes they’ll try to kill first.” Theo grabbed the pencil his doppelganger had left and picked up the work mid-equation.
“We know what they’ll all have in common—they’ll be the dimensions that version of Josie had visited before,” I said. “Those are the ones where the splinters of her soul are . . . buried, I guess.”
The splinters were too small to be collected with a Firebird, they’d told me. Nothing of Josie’s consciousness remained intact. She was dead, truly dead, and yet the Home Office had traced a bloody path to resurrection. By destroying the worlds in which Josie’s soul had existed, they hoped the splinters would slingshot back to their own universe—until finally enough splinters would come together to restore Josie body and soul.
Though if Paul was still so damaged from being splintered into four parts, what would Josie be after shattering into a thousand pieces?
“I’ve been thinking about the theoretical implications.” Paul sounded grateful to be dealing with math again rather than messy human emotions. “Triad will want to destroy source vectors as well—to take out multiple dimensions at once.”
All these years surrounded by scientists, you’d think I would’ve already learned every bit of technojargon I would ever need. Apparently not. I said, “What are source vectors?”
“Universes that generated many other universes valid for Triad’s purposes,” Mom said. No doubt my expression gave away my confusion, because she stopped and backed up. “For instance—in our world, and the Triadverse, and several others we’ve seen, Abraham Lincoln was assassinated by John Wilkes Booth. If you could find the one core universe where that event originated, and destroy that universe, you would in effect destroy all universes in which that event took place. That core universe would be a source vector. Do you see?”
“And you must understand, the timing of the significant event is completely irrelevant,” Dad cut in. “Dimensions wouldn’t just collapse. They would be . . . unmade. Even if the event took place centuries or millennia ago, destroy that source vector here and now, and it would unravel all the way back to the beginning of time.”
“Shortly after the Big Bang,” Mom interjected. We were literally talking about the apocalypse, but she still needed to be precise about when time began.
Every choice, however trivial, made a new quantum reality—another dimension unique in the multiverse. Each of the many worlds I’d visited so far, every other Marguerite I’d been: All of them would be demolished in an instant if someone found the choice back in time that led to my being born. Without that choice, that universe, none of the other Marguerites would exist. They would be unmade along with their dimensions, completely.
“Yes,” I said. “I get it. So the Home Office wants to destroy all the worlds Josie got lost in and some, uh, source vector worlds. How do we stop them? Wait. Hang on. How do they even do that? How do you destroy an entire dimension?”
The four scientists in the room exchanged glances. Their expressions looked almost . . . guilty.
I said, “Are you guys about to tell me Firebirds are way more dangerous than you ever said?”
“No!” Mom drew herself up, offended. “Honestly, Marguerite. We wouldn’t take those kinds of risks, ever.”
“Indeed not.” Dad paused, then added, “However, that doesn’t mean there’s not potential for danger with the Firebirds.”
“It’s sort of like when they fired up the Large Hadron Collider,” Theo offered. I knew all about this, even though it happened when I was hardly more than a baby. For physicists, the activation of the LHC was like the Super Bowl, the Oscars, and New Year’s Eve wrapped into one, and my parents still talked about it once in a while. “Everybody was freaking out, like, ‘ahhh, the scientists are going to create a black hole.’ Which totally didn’t happen. Because, while it’s technically possible, it’s so incredibly improbable that the LHC could run for a billion years without a black hole opening in the center of the Earth.”
Theo’s explanation helped, but still, it gave me a turn—realizing I’d been carrying even a one-billionth chance of an apocalypse around my neck.
I looked down at my Firebird, which still dangled from its chain—blood-spattered from Paul’s wound, like the torn remnants of my green cardigan and the white dress exposed beneath. For me the Firebird had always meant hope, genius, adventure. But in that moment I knew I would never forget the bloodstains.
“So, how could the Firebird destroy a dimension?” Although I figured the answer probably involved an equation longer than a Harry Potter book, I felt like I had to say something.
But Paul had learned how to translate the hidden poetry of science for me better than anyone else ever had. “Remember what I told you when we went to see the redwoods? About the fundamental asymmetry of the universe?”
I could never forget that day. Muir Woods’ beauty made me feel like Paul and I had stepped into our own precious sliver of eternity. But I remembered the physics-lesson part of it too. “Most forces in physics are symmetrical. But somewhere in the nanoseconds after the Big Bang, matter and antimatter got thrown out of whack somehow, and nobody has any idea how. That asymmetry between matter and antimatter is what makes the universe possible. Is that right?”
“. . . close enough.”
My artist brain doesn’t wrap itself around the science stuff as easily as Paul’s does. He’d never make me feel bad about it on purpose—but tact is not exactly Paul’s wheelhouse.
Hastily he added, “It’s important because the Firebirds could restore the symmetry between matter and antimatter.”
“What? How?” My mind was reeling. “Why would you ever make a device that could do that?”
Theo had overheard us. “Marguerite, that’s close to how Firebirds work in the first place. The dimensional resonances we’re always talking about, the ones that make your eyes glaze over? Those are the imbalances specific to each universe. The Firebird basically . . . surfs that imbalance, finds where it’s supposed to be, and brings you along. Tune the Firebird to attack that imbalance instead of detecting it, and . . .” Theo’s voice trailed off, and he just spread his hands outward, as if miming an explosion.
Paul, of course, couldn’t let a gesture end a scientific explanation. “The rest would take care of itself. Dimensional collapse would fold outward wthin—no. There’s no point in saying how long it would take, because the collapse would even destroy time.”
“But the Firebirds could also increase the asymmetry!” Dad said, lighting up. “It would be trickier, by a measure, but still, we could do it. The Firebird’s power might require a booster, of course . . .”
“It would.” Mom’s quicksilver mind was already a few steps ahead. “But if we could enhance the Firebirds’ power, through a fairly simple device—some sort of stabilizer we could construct in each universe, then we could increase the asymmetry in each universe. That would make it much more difficult for Triad to collapse those universes. We could slow down Triad’s work. Maybe even stop them altogether.”
It made more sense to me then—the potential within the Firebirds. Their power could unmake a world or preserve it forever. Infinite good and infinite evil, all enclosed within one locket that hung right above my heart.
By that point, Mom, Dad, and Theo were deeply embroiled in the equations. I wanted so badly to steal a few moments of privacy to talk with Paul. He needed to remember who he was, to shake off the melancholy and fatalism that still haunted him.
If he couldn’t overcome it, I hadn’t actually saved Paul. I’d only put together the pieces of a man broken beyond repair. Even thinking that made me want to hug him tightly, as if I could sink into him so deeply that my love could seal all the cracks, heal him, make him whole.
But like I said—I had more urgent problems than my love life. So did the rest of the multiverse.
“I have to go after her,” I announced. “Don’t I?”
Everyone else exchanged worried glances. I realized they’d all independently come to the conclusion that I’d have to go back into danger, but nobody had wanted to be the first to say it. Dad replied, “Sweetheart—as much as I hate this—we need to know which worlds they’re targeting. For certain. Theo’s equations will help, but the only way to be certain which dimensions are most in danger is for you to check them out.”
“I could go.” Paul’s voice was rough. “Theo too. Or the two of you. It doesn’t have to be Marguerite.”
“Yes, it does,” I insisted. His protectiveness moved me, but I couldn’t let him get away with it. I was the perfect traveler, which made me the one who slipped into each universe most easily. The one who could retain focus and control throughout. For any other trip, that might be no more than a matter of convenience. But for this? We had to respond as powerfully and quickly as we could. That meant me. I turned to my parents. “My Firebird should be able to track hers, right?”
It was Theo who finally managed to answer. “Yeah. Your two Firebirds were together for a while—we could pick up on her traces fast.”
“Do it.” I held the Firebird out to Paul. Although he hesitated, he got to work.
My mother said, “Your counterpart can’t collapse the universes without killing herself. But she could be . . . laying groundwork. Preparing each world for your eventual cooperation, or for suicide missions by others.”
If the Home Office versions of my parents and Wyatt Conley were willing to destroy entire dimensions to get Josie back, they’d think nothing of asking one person from their own world to die too. For a moment it hit me with dizzying force: Literally trillions of lives were at stake, and I was the only person with the power to save them. But I held on. “Wait. Wouldn’t the universe’s destruction slingshot her home? That’s what your Home Office selves think will happen to the splinters of Josie’s soul.”
Dad nodded. He looked as if he’d aged five years in an hour. “That’s probably what would happen to a perfect traveler—you or the Home Office’s Josie—but not to your other self or to anyone else trying to destroy a universe with a Firebird. That destruction has consequences. It forges chains. It’s as if . . . as if you were freeing a ship from anchor, but the only way to do it was by taking hold of that anchor yourself. While the ship sails free, the anchor drags you down to the bottom of the ocean. A perfect traveler would be able to overcome that, with the Firebird’s help. But anyone else would be done for.”
As unnerved as my parents were at the prospect, I felt slightly reassured. Maybe that should’ve embarrassed me—the fact that I could kind of handle the idea of an entire universe’s death if I knew I could escape. But traveling between dimensions involved enough danger already; any protection at all made me feel safer. So I let my parents show me how to use the Firebird to stabilize a universe. I refused to learn how to destroy one, because that was not a thing I was ever, ever going to do. Paul remained nearby, grave and quiet, still not looking me in the face.
It was Theo who raised a question I hadn’t considered. “Are you even going to be able to follow her?”
“What do you mean?” I said.
“If she’s not in her own dimension, then she’s already occupying a version of her in another world. Can two people leap into the same host?” He shrugged. “Seriously, no clue.”
Mom made a face. “I knew we ought to have run simulations on that.”
It didn’t seem like a big deal. Either I’d be able to do it or I wouldn’t, and if I could, I’d be in charge, because I was the perfect traveler, not Wicked. Then a ghastly possibility occurred to me. “We wouldn’t, like, fuse together or something, would we?”
At once, all four of them said, “No.” Dad helpfully added, “Different resonances, no matter what. Like oil and water, sweetheart.”
Good. I could imagine Wicked’s malevolence covering me like an oil slick, viscous and black. Better that than carrying it inside me. “You guys—remember what I told you about the Cambridgeverse?”
It took them a minute. I didn’t blame them. The story of my last chase through the dimensions was one I’d told in a rush while blood was still gushing from Paul’s arm. Paul winced at the mention of the place, because that was the world where he’d damaged my arm in a car crash that tore us all apart. But the most important aspect of the Cambridgeverse was something else entirely.
“Our counterparts are working on communicating through the dimensions,” Mom said. “You told them to reach out to us. Which means we’re poised to reach back.”
“We considered this, early on,” Dad mused, rubbing his chin in the way that meant he was either deep in thought or listening to Rubber Soul.
“If you could let them know what’s about to happen, to look out for Triad, it would give them a chance.” I looked at my torn, bloody clothing and, absurdly, felt like I ought to change before I went. When I returned home after all this and my body became observable once more, would the blood have dried? Or would it still be wet against my skin, proof of how my hands had hurt Paul?
She could’ve gone for his throat. What would I have done if I’d had to watch myself murder him?
Paul broke into my reverie, saying, “Are you ready?”
“No. But it doesn’t matter.” I reached up—he’s so tall, so heavily muscled, a Michelangelo in a world of Modiglianis. Still, I could cradle his face with my hands. “Follow me. I need all the help I can get.”
He hesitated from fear—not for himself. “Theo could go, or Sophia and Henry could finally use the Firebird for themselves—”
I whispered, “I need you.”
Paul didn’t believe me. He couldn’t, yet. But he nodded, and that had to be enough.
So I backed up, sat down in a far chair in the corner, hit the Firebird’s controls to leap after Wicked—
—and that’s why I’m now hanging from a cable about four hundred feet over the river Thames.
“Marguerite!” Paul shouts. I glance back to see him sliding out the observation window despite the cries of dismay from people nearby. My Aunt Susannah leans forward, her tears tracing streaks of mascara down her cheeks. Paul yells, “I’m going to come get you.”
“Don’t!” It costs me to shout that, because oh, God, I want him to come get me. I want him to save me. And from the glint of metal around his neck, I know this is my Paul—that he followed me, that as damaged as he is, at least something inside him still believes we can make it.
But I’m pretty sure he can’t save me. He’ll only get himself killed.
My sweaty palms slip against the cable; my fingers cramp so hard it’s like every nerve and bone is on fire. If I let go, the Londonverse Marguerite will die.
She was the first alternate self I ever entered, the first time I had to interpret the life I would’ve led in an alternate world. I think of her white, empty room. Her party-girl existence that she doesn’t enjoy a moment of. When I last stood inside her, I willed her to remember our parents—the ones robbed from her in childhood, the ones whose love I was able to share with her, at least a little. Now I know she kept those memories. She came out with Aunt Susannah to do something fun, and Paul Markov seems to have found her. Are they only friends, or something more? Regardless, he must be one of the only honest, real people in her life.
In other words—during the past few months, her life has been worth living. Now Wicked has taken it away.
That’s what they mean by “slamming doors,” I realize. They know now I’ll never do what they want. So they want to keep me from protecting these universes. The only way they can do that is by locking me out, forever.
And the only way to lock me out is to kill every Marguerite, everywhere.
My hands slip. I grab again as people scream—one hand snags the cable, but the other doesn’t. Now I’m swinging, and my shoulder hurts, and every muscle trembles. This is it.
I have to jump—but what if Wicked’s blocking my way? What if I can’t jump where she is? There’s no time to set a new course back home—if I could even touch my Firebird, which I can’t, because that would mean letting go, and if I let go—
Paul can’t see this. He can’t.
“Paul!” I cry out. “Get back inside!”
“Marguerite—no!”
I try to turn and look at him again. That’s one movement too many. My slick hand slides off the cable, and I fall.
For the first instant it’s like I’m not moving downward at all. It’s more like floating, while intense wind blows around me. But then the force of it presses in, and my stomach’s in my throat and the river’s rushing up to meet me and I’m going to die.
Firebird! As I tumble, I clutch at the Firebird beneath my shirt. It’s hard to grab it because now I’m rolling, my clothes are blowing all around me, the water’s so close, so close—I hit the controls—
My body jerks to a halt. For one terrifying instant I think this is it, I hit the river, this is the moment of death.
But no. I’m sitting in a dark, cool chamber—no, a passageway, only about four feet high. Light flickers in the distance; stone walls surround me; sand almost completely covers the floor: That’s all I know, besides the fact that I’m in another dimension, one that saved me.
The other Marguerite is dead.
She was murdered. By Wicked and—because I had a chance to save her and totally failed—by me, too.