By the light of the moon

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