The Amulet of Samarkand

concentrate, John." He had dropped his brush.
    "Sorry, it slipped, that's all. Why Samarkand, Mrs. Underwood? What's so trendy about it?"
    "I'm sure I haven't the faintest idea. If you've finished your shoes, you'd better get on with brushing your jacket."
    It was a Saturday and there were no lessons to distract Nathaniel from the thrill of what was to come, so as the day wore on he became possessed by a wildly mounting excitement. By three o'clock, several hours before it was necessary, he was already dressed in his best clothes and prowling back and forth about the house—a state of affairs that continued until his master put his head out of his bedroom and abruptly ordered him to stop.
    "Cease your tramping, boy! You're making my head throb! Or would you prefer to remain behind this evening?"
    Nathaniel shook his head numbly and descended on tiptoe to the library, where he kept himself out of trouble researching new Constraining spells for middle-ranking djinn. Time passed agreeably, and he was still busy learning the difficult incantation for the Jagged Pendulum, when Mr. Underwood strode into the room, his best overcoat flowing behind him.
    "There you are, you idiot! I've been calling for you, up and down the house! Another minute and you'd have found us gone."
    "Sorry, sir—I was reading—"
    "Not that book you weren't, you dozy fool. It's fourth-level, written in Coptic—you'd never have a hope. You were asleep and don't deny it. Right, snap to sharpish, or I really will leave you behind."
    Nathaniel's eyes had been closed at the moment his master walked in: he found it easier to memorize things that way. All things considered, this was perhaps fortunate, since he didn't have to come up with any further explanations. In an instant the book was lying discarded on the chair and he was out of the library at his master's heels and following him in a heart-pounding flurry down the hall, through the front door and out into the night, where Mrs. Underwood, in a shiny green dress and with something like a furry anaconda wound loosely round her neck, waited smiling beside the big black car.
    Nathaniel had only been in his master's car once before, and he did not remember it. He climbed into the back, marveling at the feel of the shiny leather seat and the odd, fake smell of the pine-tree odoriser dangling from the rearview mirror.
    "Sit back and don't touch the windows." Mr. Underwood's eyebrows glowered at him in the mirror. Nathaniel sat back, his hands contentedly in his lap, and the journey to Parliament began.
    Nathaniel stared out of the window as the car cruised south. The countless glowing lights of London—headlamps, street lamps, shop fronts, windows, vigilance spheres—flashed in quick succession across his face. He gazed wide-eyed, blinking hardly at all, drinking everything in. Traveling across the city was a special occasion in itself—it rarely happened to Nathaniel, whose experience of the world was confined mainly to books. Now and then, Mrs. Underwood took him on necessary bus trips to clothes and shoe stores, and once, when Mr. Underwood was away on business, he had been taken to the zoo. But he had seldom gone beyond the outskirts of Highgate, and certainly never at night.
    As usual, it was the sheer scale that took his breath away; the profusion of streets and side-roads, the ribbons of lights curving off on all sides. Most of the houses seemed very different from the ones in his master's street: much smaller, meaner, more tightly packed. Often they seemed to congregate around large, windowless buildings with flat roofs and tall chimneys, presumably factories where commoners assembled for some dull purpose. As such they didn't really interest him.
    The commoners themselves were in evidence too. Nathaniel was always amazed by how many of them there were. Despite the dark and the evening drizzle, they were out in surprising numbers, heads down, hurrying along like ants in his garden, ducking in and out of shops, or sometimes disappearing into ramshackle inns on street corners, where warm orange light shone through frosted windows. Every house like this had its own vigilance sphere floating prominently in the air above the door; whenever someone walked below, it bobbed and pulsed with a deeper red.
     
    The car had just passed one of these inns—a particularly large example opposite a subway station—when Mr. Underwood banged his fist down on the dashboard hard enough to make Nathaniel