The trick was not to listen when they said things like that. "So why haven't you squashed Errol? Made him part of your outdoors amusement park?" he said. "Since you hate him so much, and since I can't imagine he didn't try to interfere with your plans-why isn't he dead?"

The other Gerald heaved a sigh and spun around to walk face-forward again. "You tell me, Professor."

How much do I hate that I know how he thinks? "Because you never know when a top-notch First Grade wizard might come in handy."

His counterpart laughed. "You're a fiendishly clever man, Gerald Dunwoody."

"So where is he?"

More laughter, rich and filled with a genuine delight. "He and his dear friends Kirkby-Hackett and Cobcroft Minor, shadbolt-shackled to the eyeballs, the bastards, are currently slaving as kitchen hands in the greasy bowels of Government House. In fact, they're probably washing our lunch plates as we speak. And to think-Errol used to be one of Ottosland's premier airship designers. How's that for revenge?"

He couldn't help it. He laughed. The idea of superior, elegant Errol up to his elbows in dirty pots and pans...

"I thought you might appreciate the notion," the other Gerald said, grinning. "What's he doing in your world? Something menial, I hope."

He stopped laughing. Bugger. "I-don't know. Errol and I lost touch."

"I never liked him either," said Bibbie, her eyes smoldering with remembered resentment. "At parties he always used to try and look down my dress."

Stunned, Gerald stumbled. She'd said that before. No. His Bibbie had said it. At home. In the parlor. Bibbie and Monk and Mel and Reg and him, working together to solve the mystery at Wycliffe's.

God. What is wrong with me? I can't laugh with these people. She's not my Bibbie. I'm not their friend.

The other Gerald frowned. "Something the matter, Professor?"

Oh, only everything. "No."

"Not feeling sorry for Haythwaite, are you? Because if anyone deserves a good shadbolting, he does." They'd reached the end of the latest corridor, and a massively hexed door. Halting, spinning around again, the other Gerald smiled beatifically. "Saint Snodgrass be praised, Professor. I bloody love a good shadbolt."

With an effort he kept his breathing slow and steady. "I've noticed. So why aren't I wearing one?"

"Because, Professor," said his counterpart, smile fading, eyes sharply watchful again, "as you know perfectly well, you're shadbolt-proofed. Just like Sir Alec. Exactly like Sir Alec, actually. I don't suppose you'd like to explain that, would you?"

I'm what? Since when? "No, not really."

The other Gerald considered him closely. "Blimey. You didn't know you were shadbolt-proof, did you? How's that possible, a wizard with our potentia?"

Sir Alec must've done it-or had it done-at some point during his janitor training. Sneakily, and undetectably. Probably during one of those interminable tests. Was Monk a part of it? He gave new meaning to the notion of sneaky and undetectable. But why do it and not tell him? What would Sir Alec have to gain by keeping it secret?

When I get back home, he and I are going to have some words...

His heart thudded. When I get back home. But the way things were looking he wasn't going to get back, was he? Barring some kind of miracle he was trapped in this appalling, madhouse mirror world. And if that miracle didn't come in the shape of one Monk Debinger Aloysius Markham, then he was pretty sure it would never come at all.

"Professor?" said his counterpart, seeming more alarmed than cross. "Your wits are wandering again. Should I be taking you to see a doctor?"

Bloody hell, if he so much as suspects I'm a janitor that'll be it. I'll have no hope of escape.

"What?" he said, trying to sound harmless. "No. I'm fine. I'm just-" Discovering how good I am at tap-dancing on eggshells. "I'm trying to remember when it could've happened. The shadbolt-proofing."

The other Gerald raised an eyebrow. "And?"

Cover story, cover story, he needed a plausible cover story... A good janitor, Mr. Dunwoody, knows how to think on his feet.

"Well, I can't be certain," he said slowly, "but-I think it might've been when I was still a compliance officer. I needed money. You remember how skint we were. R&D was starting some paid double-blind thaumaturgic trials. Monk never told me what they were, just said they were perfectly safe. The boffins must've been testing a new shadbolt-proofing incant. They never explained either, and I didn't ask. R&D-they're so bloody hush-hush. It was about a month before the accident at Stuttley's. You didn't-that didn't happen here?"

"The accident happened," said the other Gerald. "Not the R&D trial."

He shrugged, doing his best to look innocent and bemused. "Oh. All right. Odd, isn't it, the bits and pieces of our worlds that don't fit? Well, anyway, that's the only explanation I can think of."

And truer words have never been spoken. At least not by me.

"It makes sense, Gerald," said Bibbie, slumped against the corridor wall and trying not to look bored. "Now honestly, can we see where Monk's up to and then go? Because I'd really like to-"

His sharp look having silenced her, the other Gerald folded his arms and tapped his fingers, edgily thoughtful. "What is it you do these days, Professor? Back in your world?"

Ah. Right. Damn. His counterpart's lack of curiosity had always been too good to last. What do they say? The easiest lies are the ones we tell ourselves? "I... consult, Gerald. Solve problems of a thaumaturgical nature."

"And how is it you know Sir Alec Oldman?"

Careful now, careful. "Well, I wouldn't say I know him," he said, casually dismissive. "We're slightly acquainted. We crossed paths after I got home from New Ottosland." He shrugged. "Sir Alec was just one of a long line of government busybodies I had to put up with while the dust was settling. Look-how come you don't know this? I mean, if you've got the wherewithal to pluck me from my world into yours, how can you not know who I am there?"

The other Gerald smiled thinly. "The plucking, as you call it, Professor, is a brand new feat. As it stands I wouldn't call the technique precisely refined. But don't worry. Once Monk's taken care of a few other tasks I have in mind he'll be turning his prodigious talents to the reading of alternative dimensions. In fact, we all will. But for now first things first. Just like dominoes, worlds need to fall one at a time."

It was the off-handed way the words were said that made him ill.

Bloody hell. So that's it. That's his grand plan. It's not enough to rule one world. He wants to rule them all.

"What?" said the other Gerald, reading him like a book. "Oh come on, Professor. Don't tell me you're surprised."

He didn't know what he was... except terrified and sick.

Sighing, the other Gerald unfolded his arms and pressed his left hand flat to the locked door before them. With a blinding surge of power the tangle of warding hexes on the door deactivated, blowing them all back several paces.

"What did you expect, Professor?" said his counterpart, grinning. "Keeping Monk Markham penned isn't exactly child's play." With a snap of his fingers the de-hexed door swung open. "After you."

The first thing he saw, walking into the unsealed lab with the other Gerald and Bibbie on his heels-was Reg. This world's Reg. Crammed into a cage dangling from a tall stand, tail feathers sticking out through its bars, fluffed-up and miserable. Her beak was tied shut with a length of red ribbon. When she saw him she made a strangled sound of surprise.

He stopped dead.

You bastard. You utter, utter, pillocking bastard. I will kill you for this. I swear you are dead.

With a bang and a thaumic blast, the laboratory door swung shut behind them, the warding incants reigniting.

The other Gerald put a hand on his shoulder. "Can't be too careful, Professor. Like I said, this is Monk. And look, there she is. Reg. Didn't I say you'd be seeing her?"

He swallowed acid and bile. "Get her out of that damned cage, Gerald."

"I will," the other Gerald said. "In a minute. Say hello to Monk, why don't you?"

Oh, yes. There was Monk. This world's Monk. Shadbolted like Attaby and the others, and barricaded behind a veritable wall of thaumaturgical apparatus, monitors and etheretic flux capacitors and test tubes and various bits and pieces he couldn't put a name to, wearing an expression that could only be described as stunned.

"Gerald..." he whispered.

"Actually," said the other Gerald, "to avoid confusion, I'm calling him Professor. Your sister's calling him Gerry. You can call him whatever you like-but I'm the only Gerald here. Understood?"

"What?" said the other Monk. He shook himself like a wet dog. "Oh. Yeah. Sure. Sorry."

The small, windowless laboratory stank of discharged thaumaturgics and the ether quivered with echoes of thaumic activity. A table shoved against the right-hand wall was littered with dirty plates and cutlery. Crowded with discarded mugs. There was a single gas ring in the corner unlit, and an icebox beside it. A narrow door in the left-hand wall offered a glimpse of bathroom. Along the same wall was a bedroll, a pillow and a heap of blankets. How long did Bibbie say this Monk had been here? Three days and counting? The lab was a cage.

"So," said the other Gerald, as his Monk Markham continued to stare. "How have you been getting on, old chap?"

Monk blinked. "Getting on?"

"Don't play the idiot, Monk," Bibbie snapped. "Because you know what happens when you play the idiot. Gerald gets cranky, you get punished and I'm the one who has to listen to you scream. So if you love me like a big brother's supposed to, just answer the bloody question."

"Bibbie," said the other Monk. And now he was staring like he'd never seen her before. Reg, in her horrible cage, banged her beak against the bars. Monk flinched. "Yes. Of course I love you, Bibs." He looked at his Gerald. "I'm sorry. It's not finished."

"Not finished?" said the other Gerald, his voice silky with displeasure. "Why not? Monk, you told me all you needed was a few more days in absolute solitude, so you could focus. You swore to me that in a few more days it would be done. So why isn't it done? You know the timetable. You know what's expected. Monk, I can't tell you how disappointed I am. Bibbie-"

Bibbie looked at him. "Yes, Gerald?"

"Now would be a good time to stick your fingers in your ears."

As Bibbie turned away, clapping her hands to the sides of her head, the other Gerald snapped his fingers. And Monk-the other Monk-dropped howling to the floor.

"Stop it!" Gerald shouted, lunging at his counterpart. "Bloody hell, Gerald. Stop it! He's your friend!"

"Mind your own business, Professor," the other Gerald retorted, and clenched his fist.

The ether surged and he flew through the air to smack into the nearest bit of wall, flicked aside as though he were a pestering fly. He struck the plastered brick so hard bright lights burst before his good eye and all the stale lab air was punched out of his lungs. He fell to his hands and knees, gasping, and watched himself watch Monk's suffering with no sympathy at all.

Reg was banging her head against the cage.

And then Bibbie tugged at the other Gerald's arm. "That's enough. If you need him you can't keep hurting him like this."

The other Gerald spared her an irritated glance then snapped his fingers again. Monk stopped howling.

"You're a bloody idiot, mate," the other Gerald said, sounding weary. "When you know what that shadbolt can do, why the hell did you have to go and disappoint me?"

Sheet-white, the other Monk staggered to his feet. "You think I wanted to?" he said raggedly. "I've been working non-stop, Gerald. I've been slaving around the clock. I need help. This bloody contraption-I don't have what it takes to get the job done. You're the only wizard in the world with the potentia to make this work. You'll have to stay and help me. It's the only way you'll have it in time."

"Well, that's not going to happen," said the other Gerald, frowning. "I've got about a million things to do, Monk."

Bracing himself, the other Monk lifted his chin. "Then you'll have to stay disappointed, mate. Because I'm officially at the end of the thaumaturgical road."

The other Gerald laughed. "No, you're not, Monk. You should've let me finish. Why d'you think I brought you a visitor? I can't stay here and help you-but he can."

CHAPTER TWENTY-TWO.

Me?" Gerald stepped back. "Ah-no. No, I don't think so. For one thing I don't have a clue what he's-your Monk's-working on, and for another-you may have completely abandoned your principles, Gerald, but I haven't."

"Oh," said the other Gerald. "D'you know, Professor, that hurts. I mean, you abandoned them for Lional."

"I did," he said steadily. "To my everlasting shame."

"Everlasting shame?" The other Gerald raised an eyebrow. "Really? Because it looks to me like you got over it all right. So what's the problem?"

"That," he said, "is a bloody stupid question, and you know it."

"What I know, Professor," said the other Gerald, prowling towards him, "is that Ottosland is on the brink of attack. Your country, your countrymen, are in terrible peril. If you don't help me then the blood of countless innocents will run in the streets."

"Not because of anything I've done," he retorted. "From what I can tell, Gerald, you started this fight. And you can finish it by standing down. Besides. This isn't my country."

Halting, his counterpart smiled. "Well, if we're going to talk about saying stupid things, Professor, you'd win a prize for that fatuous statement. You can't fool me. You care. You care too much. It's always been your greatest flaw."

"I prefer to think of it as my saving grace."

The other Gerald shrugged. "If I had time for semantics, Professor, I'd happily argue the point. But I don't. So here's the thing. I didn't risk a temporal-dimensional implosion and give myself a skull-shattering headache bringing you here just so you could stand around carping at me like that bloody bird. I risked those things to make sure my plans come to fruition. You are going to help me. You aren't going to argue. Because if you refuse to cooperate not only will your precious bloody Melissande get the chop, she'll just be one of many victims you can chalk up to your short-sighted, sanctimonious pig-headed lack of cooperation."

"Gerald!" said the other Monk, his voice rough. Close to breaking. "Please. Do what he says. He really will kill Melissande. And I love her, mate. She's the only woman I'll ever love. I'm begging you, Gerald. Don't let her die."

Oh, God. "I'm sorry," he said at last, and made himself look at the stranger wearing Monk's face. "But if your Melissande's anything like mine, she wouldn't want to be used like this. Whatever that machine is you're making for this bastard? It's not good, Monk. It's going to hurt a lot of people. And I swore after Lional I'd never capitulate again. No matter what was done to me. No matter what was threatened."

As the other Monk turned away, distraught, and Bibbie groaned, so sarcastic, the other Gerald laughed and sauntered to the birdcage. "How tediously bloody noble of you, Professor. I swear, I'm crying. Well, I'm crying on the inside. But that's only so I don't have to heave. Saint Snodgrass's bunions! What a dreary pillock you've turned out to be!" A finger snap, and Reg's hexed cage door sprang open. "And how bloody glad am I that I didn't listen to this bitch's nagging and face down Lional without some extra ammunition." In a blur of motion he reached into the cage and snatched the other Reg out of it. Held her up by the throat, wings dangling, eyes rolling. "So how noble are you really, Professor?" he taunted. "Noble enough to watch me break the bird's neck like a twig?"

"No, don't hurt her!" the other Monk shouted, terrified. "Please, Gerald-don't let him-God, you can't-you can't-"

But he had to. He had to make a stand. Make it clear to his mad other self that no matter what there'd be no cooperation. He closed his eyes. This wasn't his Reg, but even so...

I'm sorry.

A stir in the ether and an agonized, strangled shout. And then, despite his cruel shadbolt, the other Monk was lashing out, tossing obfuscation incants and slippy-finger hexes and anything else he could think of to make the other Gerald let go.

For all the good it did, he might as well have been spitting.

Laughing, the other Gerald deflected the thaumaturgical attack and retaliated with a brutal strike of his own. The other Monk hit the lab's low ceiling then dropped to the floor with bone-rattling force. Shrieking, Bibbie threw herself under the nearest table. Captive Reg flapped her wings desperately, struggling to get free. And Monk-the other Monk- The other Monk staggered to his feet, lurched around his lab bench and came straight for him, a mad light in his eyes. "You bastard! Bastard! Let Melissande die, would you? Let Reg die? Not while I'm still breathing, sunshine!"

The last thing he wanted to do was hurt this other Monk. He tried to dodge but the lab was crowded with benches and equipment. There was nowhere to run. As the man who looked like his best friend crashed him to the floor he caught a glimpse of the other Gerald laughing as he shoved his Reg back in the cage.

Panting, the other Monk grabbed him by the hair and thudded his head onto the concrete. "I don't know you! I don't know you!"