THROUGH this evenings tide of faces unregistered, unrecognized, amid hurrying black shoes, furled umbrellas, the crowd descending like a single organism into the stations airless heart, comes Shinya Yamazaki, his notebook clasped beneath his arm like the egg case of some modest but moderately successful marine species.

Evolved to cope with jostling elbows, oversized Ginza shopping bags, ruthless briefcases, Yamazaki and his small burden of information go down into the neon depths. Toward this tributary of relative quiet, a tiled corridor connecting parallel escalators.

Central columns, sheathed in green ceramic, support a ceiling pocked with dust-furred ventilators, smoke detectors, speakers. Behind the columns, against the far wall, derelict shipping cartons huddle in a ragged train, improvised shelters constructed by the city's homeless. Yamazaki halts, and in that moment all the oceanic clatter of commuting feet washes in, no longer held back by his sense of mission, and he deeply and sincerely wishes he were elsewhere.

He winces, violently, as a fashionable young matron, features swathed in Chanel micropore, rolls over his toes with an expensive three-wheeled stroller. Blurting a convulsive apology, Yamazaki glimpses the infant passenger through flexible curtains of some pink-tinted plastic, the glow of a video display winking as its mother trundles determinedly away.

Yamazaki sighs, unheard, and limps toward the cardboard shelters. He wonders briefly what the passing commuters will think, to see him enter the carton fifth from the left. It is scarcely the height of his chest, longer than the others, vaguely coffin-like, a flap of thumb-smudged white corrugate serving as its door.

Perhaps they will not see him, he thinks. Just as he himself has never seen anyone enter or exit one of these tidy hovels. It is as though their inhabitants are rendered invisible in the transaction that allows such structures to exist in the context of the station. He is a student of existential sociology, and such transactions have been his particular concern.

And now he hesitates, fighting the urge to remove his shoes and place them beside the rather greasy-looking pair of yellow plastic sandals arranged beside the entrance flap on a carefully folded sheet of Parco gift wrap. No, he thinks, imagining himself waylaid within, struggling with faceless enemies in a labyrinth of cardboard. Best he not be shoeless.

Sighing again, he drops to his knees, the notebook clutched in both hands. He kneels for an instant, hearing the hurrying feet of those who pass behind him. Then he places the notebook on the ceramic tile of the station's floor and shoves it forward, beneath the corrugate flap, and follows it on his hands and knees.

He desperately hopes that he has found the right carton.

He freezes there in unexpected light and heat. A single halogen fixture floods the tiny room with the frequency of desert sunlight. Unventilated, it heats the space like a reptile's cage.

'Come in, says the old man, in Japanese. 'Don't leave your ass hanging out that way. He is naked except for a sort of breechclout twisted from what may once have been a red T-shirt. He is seated, cross-legged, on a ragged, paint-flecked tatami mat. He holds a brightly colored toy figure in one hand, a slender brush in the other. Yamazaki sees that the thing is a model of some kind, a robot or military exoskeleton. It glitters in the sun-bright light, blue and red and silver. Small tools are spread on the tatami: a razor knife, a sprue cutter, curls of emery paper.

The old man is very thin, clean-shaven but in need of a haircut. Wisps of gray hair hang on either side of his face, and his mouth is set in what looks to be a permanent scowl of disapproval. He wears glasses with heavy black plastic frames and archaically thick lenses. The lenses catch the light.

Yamazaki creeps obediently into the carton, feeling the door flap drop shut behind him. On hands and knees, he resists the urge to try to bow.

'He's waiting, the old man says, his brush tip poised above the figure in his hand. 'In there. Moving only his head.

Yamazaki sees that the carton has been reinforced with mailing tubes, a system that echoes the traditional post-and-beam architecture of Japan, the tubes lashed together with lengths of salvaged poly-ribbon. There are too many objects here, in this tiny space. Towels and blankets and cooking pots on cardboard shelves. Books. A small television.

'In there? Yamazaki indicates what he takes to be another door, like the entrance to a hutch, curtained with a soiled square of melon-yellow, foam-cored blanket, the sort of blanket one finds in a capsule hotel. But the brush tip dips to touch the model, and the old man is lost in the concentration this requires, so Yamazaki shuffles on hands and knees across the absurdly tiny space and draws the section of blanket aside. Darkness.

'Laney-San?

What seems to be a crumpled sleeping bag. He smells sickness. 'Yeah? A croak. 'In here.

Drawing a deep breath, Yamazaki crawls in, pushing his notebook before him. When the melon-yellow blanket falls across the entrance, brightness glows through the synthetic fabric and the thin foam core, like tropical sunlight seen from deep within some coral grotto.

'Laney?

The American groans. Seems to turn, or sit up. Yamazaki can't see. Something covers Laney's eyes. Red wink of a diode. Cables. Faint gleam of the interface, reflected in a thin line against Laney's sweat-slick cheekbone.

'I'm deep in, now, Laney says, and coughs.

'Deep in what?

'They didn't follow you, did they?

'I don't think so.

'I could tell if they had.

Yamazaki feels sweat run suddenly from both his armpits, coursing down across his ribs. He forces himself to breathe. The air here is foul, thick. He thinks of the seventeen known strains of multi-drug-resistant tuberculosis

Laney draws a ragged breath. 'But they aren't looking for me, are they?

'No, Yamazaki says, 'they are looking for her.

'They won't find her, Laney says. 'Not here. Not anywhere. Not now.

'Why did you run away, Laney?

'The syndrome, Laney says and coughs again, and Yamazaki feels the smooth, deep shudder of an incoming maglev, somewhere deeper in the station, not mechanical vibration but a vast pistoning of displaced air. 'It finally kicked in. The 5-SB. The stalker effect. Yamazaki hears feet hurrying by, perhaps an arm's length away, behind the cardboard wall.

'It makes you cough? Yamazaki blinks, making his new contact lenses swim uncomfortably.

'No, Laney says and coughs into his pale and upraised hand. 'Some bug. They all have it, down here.

'I was worried when you vanished. They began to look for you, but when she was gone-

'The shit really hit the fan.

'Shit?

Laney reaches up and removes the bulky, old-fashioned eyephones. Yamazaki cannot see what outputs to them, but the shifting light from the display reveals Laney's hollowed eyes. 'It's all going to change, Yamazaki. We're coming up on the mother of all nodal points. I can see it, now. It's all going to change.

'I don't understand.

'Know what the joke is? It didn't change when they thought it would. Millennium was a Christian holiday. I've been looking at history, Yamazaki. I can see the nodal points in history. Last time we had one like this was 1911.

'What happened in 1911?

'Everything changed.

'How?

'It just did. That's how it works. I can see it now'

'Laney, Yamazaki says, 'when you told me about the stalker effect, you said that the victims, the test subjects, became obsessed with one particular media figure.