Whack! Smack over the left side of my face.

We look at each other: me trembling with shock and Mam angrier than I've ever seen her, and—I reckon—knowing she's just broken something that'll never be mended. I leave the room without a word, as if I've just won an argument.

I only cry a bit, and it's shocked crying, not boo-hoo crying, and when I'm done I go to the mirror. My eyes're a bit puffy, but a bit of eyeliner soon sorts that out ... Dab of lippy, bit of blusher ... Sorted. The girl in the mirror's a woman, with her cropped black hair, her Quadrophenia T-shirt, her black jeans. "I've got news for you," she says. "You're moving in with Vinny today." I start listing the reasons why I can't, and stop. "Yes," I agree, giddy and calm at once. I'm leaving school, as well. As from now. The summer holidays'll be here before the truancy officer can fart, and I'm sixteen in September, and then it's stuff you, Windmill Hill Comprehensive. Do I dare?

I dare. Pack, then. Pack what? Whatever'll fit into my big duffel bag. Underwear, bras, T-shirts, my bomber jacket; makeup case and the Oxo tin with my bracelets and necklaces in. Toothbrush and a handful of tampons—my period's a bit late so it should start, like, any hour now. Money. I count up £13.85 saved in notes and coins. I've £80 more in my TSB bankbook. It's not like Vinny'll charge me rent, and I'll look for a job next week. Babysitting, working in the market, waitressing: There's loads of ways to earn a few quid. What about my LPs? I can't lug the whole collection over to Peacock Street now, and Mam's quite capable of dumping them at the Oxfam shop out of spite, so I just take Fear of Music, wrapping it carefully in my bomber jacket and putting it into my bag so it won't get bent. I hide the others under the loose floorboard, just for now, but as I'm putting the carpet back, I get the fright of my life: Jacko's watching me from the doorway. He's still in his Thunderbirds pajamas and slippers.

I tell him, "Mister, you just gave me a heart attack."

"You're going." Jacko's got this not-quite-here voice.

"Just between us, yes, I am. But not far, don't worry."

"I've made you a souvenir, to remember me by." Jacko hands me a circle of cardboard—a flattened Dairylea cheese box with a maze drawn on. He's mad about mazes, is Jacko; it's all these Dungeons & Dragonsy books him and Sharon read. The one Jacko's drawn's actually dead simple by his standards, made of eight or nine circles inside each other. "Take it," he tells me. "It's diabolical."

"It doesn't look all that bad to me."

" 'Diabolical' means 'satanic,' sis."

"Why's your maze so satanic, then?"

"The Dusk follows you as you go through it. If it touches you, you cease to exist, so one wrong turn down a dead end, that's the end of you. That's why you have to learn the labyrinth by heart."

Christ, I don't half have a freaky little brother. "Right. Well, thanks, Jacko. Look, I've got a few things to—"

Jacko holds my wrist. "Learn this labyrinth, Holly. Indulge your freaky little brother. Please."

That jolts me a bit. "Mister, you're acting all weird."

"Promise me you'll memorize the path through it, so if you ever needed to, you could navigate it in the darkness. Please."

My friends' little brothers are all into Scalextric or BMX or Top Trumps—why do I get one who does this and says words like "navigate" and "diabolical"? Christ only knows how he'll survive in Gravesend if he's gay. I muss his hair. "Okay, I promise to learn your maze off by heart." Then Jacko hugs me, which is weird 'cause Jacko's not a huggy kid. "Hey, I'm not going far ... You'll understand when you're older, and—"

"You're moving in with your boyfriend."

Excerpted from The Bone Clocks by David Mitchell. Copyright © 2014 by David Mitchell. Excerpted by permission of Random House. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.