The Amulet of Samarkand

Faquarl's voice sounded behind me.
    "Bartimaeus, stop!"
    "Didn't you see them?" I yelled back over my wing. "They'll be on us in moments!" I redoubled my speed, ignoring Faquarl's urgent calls. Rooftops flashed below me, then the mucky expanse of the Thames, which I crossed in record time, then—
    The Tower of London, just as before. The flying figures were now shooting out in all directions, each group following a search sphere. One lot was heading my way. Every instinct told me to turn tail and flee, but I was too confused. I alighted upon a rooftop. A few moments later, Faquarl appeared beside me, panting and swearing fit to burst.
    "You fool! Now we're back where we started!"
    A penny dropped. "You mean—"
    "The first Tower you saw was a mirror illusion. We should have gone straight through it.[4] Lovelace warned me of it—and you wouldn't wait to listen! Curse my injured wing and curse you, Bartimaeus!"
     
    [4] Mirror illusion: a particularly cunning and sophisticated spell. It forms false images of a large-scale object—e.g. an army, a mountain, or a castle. They are flat and dissolve away as you pass through them. Mirror illusions can baffle even the cleverest opponent. As demonstrated here.
     
    The battalion of flying djinn was crossing the outer walls. Barely a street's distance separated us. Faquarl hunched dismally behind a chimney. "We'll never outfly them."
    Inspiration came. "Then we won't fly. We passed some traffic lights back there."
    "So what?" Faquarl's normal urbanity was wearing a little thin.
    "So we hitch a ride." Keeping the building between me and the searchers, I swooped off the roof and down to an intersection, where a line of cars was halted up at a red light. I landed on the pavement, near the back of the queue, with Faquarl close on my heels.
    "Right," I said. "Time to change."
    "What to?"
    "Something with strong claws. Hurry up, the lights are turning green." Before Faquarl could object, I hopped off the pavement and under the nearest car, trying to ignore the repellent stench of oil and petrol fumes and the sickening vibrations that intensified as the unseen driver revved the engine. With no regret, I bade farewell to the raven and took on the form of a stygian implet, which is little more than a series of barbs on a tangle of muscle. Barbs and prongs shot out and embedded themselves in the filthy metal of the undercarriage, securing me fast as the car began to inch forward and away. I had hoped Faquarl would be too slow to follow, but no such luck: another implet was right beside me, grimly hanging on between the wheels and keeping his eyes fixed on me the whole time.
    We didn't talk much during the journey. The engine was too loud. Besides, stygian implets go in for teeth, not tongues.
    An endless time later, the car drew to a halt. Its driver got out and moved away. Silence. With a groan, I loosened my various intricate holds and dropped heavily to the tarmac, groggy with motion sickness and the smell of technology.[5] Faquarl was no better off. Without speaking, we became a pair of elderly, slightly manky cats, which hobbled out from under the car and away across a stretch of lawn toward a thick clump of bushes. Once there, we finally relaxed into our preferred forms.
     
    [5] Many modern products—synthetic plastics, metal alloys, the inner workings of machines—carry so much of the human about them that they afflict our essence if we get too close for too long. It's probably some sort of allergy.
     
    The cook sank down upon a tree stump. "I'll pay you back for that, Bartimaeus," he gasped. "I've never had such torture."
    The Egyptian boy grinned. "It got us away, didn't it? We're safe."
    "One of my prongs punctured the petrol tank. I'm covered with the stuff. I'll come up in a rash—"
    "Quit complaining." I squinted through the foliage: a residential street, big semis, lots of trees. There was no one in sight, except for a small girl playing with a tennis ball in a nearby drive. "We're in some suburb," I said. "Outskirts of London, or beyond." Faquarl only grunted. I cast a sly side glance. He was re-examining the wound Baztuk had given him. Looked bad. He'd be weakened.
    "Even with this gash I'm more than a match for you, Bartimaeus, so come and sit down." The cook gestured impatiently. "I've something important to tell you."
    With my usual obedience, I sat on the ground, cross-legged, the way Ptolemy used to do. I didn't get too close. Faquarl reeked of