By the light of the moon

extraordinary tactility of this
light. With a start and with a little grimace of revulsion, she
wiped at her face with one hand, as though she had walked into the
clingy spokes and spirals of a spider's web.
    Dylan wasn't a science buff, except as knowledge in the fields
of biology and botany served to improve the accuracy of his
depiction of the natural world in his paintings, and he didn't
qualify as even an armchair physicist. But he knew that deadly
types of radiation, including that from a nuclear bomb, never
stimulated the sense of touch, just as the less mortal X-rays
administered in a dentist's office never caused the slightest
tingle when passing through your jaw; the survivors of the historic
blast in Hiroshima, who later died of radiation poisoning, had
never felt the many billions of subatomic particles piercing their
bodies.
    Although he doubted that the flesh-prickling effect of the light
represented a danger, he hesitated anyway. He might have pulled the
door shut, might have turned away, leaving his curiosity
unsatisfied, if Shep had not been on the other side and perhaps in
need of help.
    When he spoke his brother's name, he didn't receive a reply.
This came as no surprise. While Shep was more talkative than your
average stone, he often proved no more responsive than
granite. Dylan called out again, and pushed open the door after the
second silence. He was prepared for the sight of the shower stall.
The toilet, too. The sink, the mirror, the towel rack.
    What Dylan had not been prepared for, what caused his adrenal
gland to squirt another dose of epinephrine into his bloodstream,
what caused his guts to tweak in a less than pleasant fashion was
the doorway in the wall beside the sink, where earlier no door had
been. The source of the strange red light lay beyond this
postern.
    Hesitantly, he crossed the threshold into the bathroom.
    Doorway didn't accurately convey the nature of this
mysterious opening. It wasn't rectangular, but round, like a hatch
in a bulkhead between two compartments in a submarine. Hatch didn't
qualify as the mot juste , either, because no architrave
surrounded the hole in the wall.
    Indeed, the six-foot-diameter opening itself appeared to lack
depth, as though it had been painted on the wall. No header, no
jamb, no threshold. And yet the scene beyond appeared convincingly
three-dimensional: a radiant red tunnel dwindling to a disc of blue
light.
    Dylan had seen masterpieces of trompe l'oeil in which
artists, relying on nothing more than paint and their talent, had
created illusions of space and depth that completely deceived the
eye. This, however, was not merely a clever painting.
    For one thing, the murky red glow from the luminous walls of the
tunnel penetrated to the motel bathroom. This queer light glimmered
in the vinyl floor, reflected off the mirror – and crawled on his exposed skin.
    Furthermore, those tunnel walls ceaselessly turned, as if this
were a passage in a carnival funhouse, a sideshow monkey barrel in
which to test your balance. Trompe 1'oeil painting could produce
the illusion of depth, texture, and reality – but it could
not provide an illusion of motion.
    Jilly stepped into the bathroom beside Dylan.
    He placed a restraining hand on her shoulder.
    Together they marveled at the tunnel, which appeared to be at
least thirty feet long.
    Impossible, of course. Another motel unit backed up to this one;
plumbing-to-plumbing design saved construction costs. A hole cut in
the wall would reveal only another bathroom identical to theirs.
Not a tunnel, never a tunnel. There was nothing to bore a tunnel through ; the bathroom had not been built into the side of a
mountain.
    Nonetheless, a tunnel. He closed his eyes. Opened them. Tunnel.
Six feet in diameter. Glowing, revolving.
    Welcome to the monkey barrel. Buy a ticket, test your
balance.
    In fact, someone had already entered the barrel. Silhouetted
against a disc of azure light, a man stood at the far end of the
passageway.
    Dylan had no doubt that the distant figure was Shep. Out there
past the terminus of the tunnel, his back to them, Shepherd gazed
into the blue beyond.
    So if under Dylan the floor seemed to shift, if he felt that he
might drop through a hole into a shaft as deep as eternity, this
was not an associated effect of the tunnel. This was just a
psychological response to the sudden perception that reality, as
he'd always known it, was less stable than he had assumed.
    Breathing hard, exhaling words