He remained aware of Jilly beside him, still braced for disaster with her sneakered feet against the dashboard, frantically struggling to shrug into her safety harness and to buckle herself to the seat. Peripheral vision suggested and a glance confirmed that she'd fallen into a state of unadulterated terror. He supposed she was saying something to him, shouting objections to his heedless, headlong westward rush. In fact he could hear her voice, which had grown hollow and low and distorted, as though hers was a taped recitation being replayed at the wrong speed; he couldn't understand a word.

Before the speedometer registered 100, to an even greater degree when it read 101, each irregularity in the pavement translated with magnified effect to the steering wheel, which tried to spin out of his grip. Fortunately, the sudden sweat that earlier slathered his face and moistened his palms had already dried in the steady blast of air conditioning. He maintained control at 102, at 103, but though he held the wheel, he couldn't lift his foot from the accelerator.

Greater velocity didn't at all diminish his overwhelming need for speed, and indeed, the faster the Expedition went, the greater Dylan's sense of urgency grew, and the more compelled he became to push the vehicle still harder, more relentlessly. He felt drawn by black-hole gravity, across the event horizon, beyond which neither matter nor radiation could escape the power of a crushing vortex. Move, move, MOVE became his mantra, movement with no deducible purpose, movement for movement's sake, westward, westward, on the trail of the long-lost sun and the still visible but receding moon.

Perhaps this frenzied plunge toward an unknown yet desperately needed object was how Frankenstein's unluckiest injected subjects felt in the frantic moments before their plummeting IQs dropped them through a trapdoor to the land of imbecility, idiocy.

If it doesn't obliterate your personality or totally disrupt your capacity for linear thinking, or reduce your IQ by sixty points…

Ahead loomed the town that they had departed with such haste a short while ago, when they'd feared nothing more than the appearance of a train of black Suburbans in the rearview mirror, gleaming like Death's gondolas given wheels.

Dylan expected to experience an irresistible pull toward the freeway exit near the motel where Jilly's Coupe DeVille had served as their tormentor's flaming casket. A glance at the instrument panel – 104 miles per hour – caused his briskly trotting heart to break into a gallop. He couldn't navigate that curving ramp at half their current velocity. He prayed that if compelled to leave the interstate, he would overcome this rage for speed in time to avoid crashing through the guardrail and tumbling to the bottom of an embankment in a test-to-destruction of Ford Motor Company's safety engineering.

As they approached the dreaded exit, he tensed, but he felt no strange attraction for it. They shot past the off-ramp as though they were a stunt team gearing up toward a jump over sixteen parked buses.

South of the interstate, among the bright clutter of road-service enterprises, the motel sign glowed with an ominous quality. The red neon inspired thoughts of blood, fire; it brought to mind myriad scenes of Hell as conceived with morbid passion by everyone from pre-Renaissance artists to contemporary comic-book illustrators.

The rhythmic spurt of roof-rack beacons atop emergency vehicles splashed the walls of the distant motel. Thin ribbons of gray smoke still rose from the charred hulk of the Coupe DeVille.

In little more than half a minute, the smoldering carnage lay a mile behind them. They were closing rapidly on the second of two exits that served the town, more than three miles west of the first.

As their speed at last began to fall rapidly and as Dylan flicked the right-turn signal, Jilly might have thought that he'd regained control of himself. He was, however, no more the master of his fate than he'd been when he'd spun the SUV out of the eastbound lanes and crossed the median. Something called him, like a siren to a sailor, and he continued to be powerless to resist this unknown summoning force.

He took the western exit too fast, but not fast enough to slide or roll the Expedition. At the bottom of the ramp, when he saw no traffic on the quiet surface street, he ran the stop sign without hesitation and turned left into a residential area, with utter disregard for the laws of man and physics.

'Euca, euca, euca, eucalyptus,' Dylan heard himself chanting, speaking without volition, spooked by this new turn of events not solely because it was weird, but because he sounded dismayingly like Shep. 'Eucalyptus, eucalyptus five, no, not five, eucalyptus six, no, eucalyptus sixty.'

Although visually oriented, he was a bookish man as well; and over the years he'd read a few novels about people seized by mind-controlling aliens, one about a girl possessed by a demon, one about a guy ridden by the ghost of a dead twin, and he supposed that this was how he might feel if, in reality, an evil extraterrestrial or a malevolent spirit took up residence in his body with the power to override his will. He wasn't aware, however, of any invading entity squirming within his flesh or crawling the surface of his brain; he remained rational enough to reason that what had gotten into him was nothing more than the mysterious contents of that 18-cc syringe.

This analysis did not reassure him.

For no reason, just because it felt right, he turned left at the first cross street, drove three blocks, his voice growing more urgent by the moment, insistent and loud enough to drown out whatever Jilly was saying: 'Eucalyptus six, eucalyptus zero, eucalyptus five, sixty-five, no, five sixty, maybe, or fifty-six…'

Although he had slowed to forty miles an hour, he almost sped past the street sign bearing the name of the very tree about which he had been babbling: EUCALYPTUS AVENUE.

He tapped the brakes, wheeled left, climbed and descended the curb at the corner of the intersection, drove into Eucalyptus Avenue.

Too narrow to be correctly called an avenue, hardly wider than a lane, the street featured not a single eucalyptus, as far as he could discern, but was flanked by Indian laurels and by old olive trees with exquisitely gnarled trunks and limbs that cast a wild wickerwork of shadows in the amber glow of streetlamps. Either the eucalyptuses had perished and had been replaced ages ago, or the street had been named by an arboricultural ignoramus.

Beyond the trees stood modest houses, old but for the most part well maintained: stucco casetas with barrel-tile roofs, suburban ranch-style houses with clean lines but little character, here and there a two-story structure that seemed to have been displaced from Indiana or Ohio.

He began to accelerate, but then impetuously braked and swung the Expedition to the curb in front of 506 Eucalyptus Avenue. At the end of a brick walkway stood a two-story clapboard house with a deep front porch.

Switching off the engine, popping the release on his safety harness, he said, 'Stay here with Shep.'

Jilly responded, but Dylan didn't understand her. Although from this point he would be on foot, the urgency and sense of mission that had swiveled him out of an eastward flight into this westward odyssey had not diminished. His heart still knocked so forcibly and so fast that the inner percussion half deafened him, and he had neither the patience nor the presence of mind to ask her to repeat herself.

When he threw open the driver's door, she snared a handful of his Hawaiian shirt and held fast. She had the grip of a griffin; her fingers hooked like talons in the fabric.

Dark anxiety clouded her beauty, and her sable-brown eyes, once as limpid and sharp with purpose as those of a sentinel eagle, were muddy with worry. 'Where did you go?' she demanded.