Back a step. Sometimes a person thought too much. Arkady returned to the bed, mimed opening the attaché case, slipping something from the shoe sack and moving to the closet. As the closet opened, its lights lent a milky glow to the bed of salt still covering the floor. The top of the mound showed the same signs of activity that Arkady had seen before: a scooping here, a setting something down there. Arkady saw confirmation in a brown dot of blood tunneled through the salt, from Ivanov leaning over. Ivanov had removed the thing from the shoe sack, set it on the salt and then… what? The saltshaker might have fit nicely into the depression in the middle of the salt. Arkady pulled open a drawer of monogrammed long-sleeved shirts in a range of pastels. He flipped through them and felt nothing, shut the drawer and heard something shift.

Arkady opened the drawer again and, in the back, beneath the shirts, found a bloody handkerchief wrapped around a radiation dosimeter the size of a calculator. Salt was embedded in the seam of its red plastic shell. Arkady held the dosimeter by the corners to avoid latent fingerprints, turned it on and watched the numbers of the digital display fly to 10,000 counts per minute. Arkady remembered from army drills that an average reading of background radioactivity was around 100. The closer he held the meter to the salt, the higher the reading. At 50,000 cpm the display froze.

Arkady backed out of the closet. His skin was prickly, his mouth was dry. He remembered Ivanov hugging the attaché case in the elevator, and his backward glance to the elevator camera. Arkady understood that hesitation now. Pasha was bracing himself at the threshold. Arkady turned the meter off and on, off and on, until it reset. He made a circuit of Pasha's beautiful white apartment. The numbers dramatically shuffled and reshuffled with every step as he picked his way like a blind man with a cane around flames he sensed only through the meter. The bedroom burned, the office burned, the living room burned, and at the open window, curtains dragged by the night wind desperately whipped and snapped to point the fastest way out of an invisible fire.

Pripyat had been a city of science built on straight lines for technicians, and it shimmered in the light of a rising moon. From the top floor of the municipal office, Arkady overlooked a central plaza wide enough to hold the city's entire population on May Day, Revolution Day, International Women's Day. There would have been speeches, national songs and dances, flowers in cellophane presented by neatly pressed children. Around the plaza were the broad horizontals of a hotel, restaurant and theater. Tree-lined boulevards spread to apartment blocks, wooded parks, schools and, a mere three kilometers away, the constant red beacon of the reactor.

Arkady sank back into the shadows of the office. He had never thought his night vision was particularly good, but he saw calendars and papers strewn on the floor, fluorescent tubes crushed, file cabinets facedown around a nest of blankets and the glint of empty vodka bottles. A poster on the wall proclaimed something lost in faded letters: confident of the future was all Arkady could make out. In camouflage fatigues, he himself was fairly hard to see. The pinprick of a match being struck drew him closer to the window. He'd missed where. The buildings were blank, streetlamps broken. The forests pressed increasingly closer, and when the wind died, the city was utterly still, without a single light, without the progress of a car or the sound of a footstep. Around the city there was not one human intrusion until the orange bud of a cigarette stirred directly across the plaza in the dark mass of the hotel.

Arkady had to use a flashlight in the stairway because of the debris-bookcases, chairs, drapes and bottles, always bottles, and everything covered by a chalky residue of disintegrating plaster that formed a cavern's worth of stalactites and stalagmites. Even if there had been power, the elevators were rusted shut. From outside, a building might seem intact. Inside, this one resembled a target of artillery, with walls exploded, pipes ruptured and floors heaved by ice.

On the ground floor, Arkady turned off the light and went at a lope around the plaza. The hotel entrance doors were chained together. No matter; he walked through missing panes of glass, turned on the flashlight, crossed the lobby and maneuvered as silently as possible around service trolleys piled on the steps. On the fourth floor, the doors were open. Beds and bureaus materialized. In one room, the wallpaper had curled off in enormous scrolls; in another, the ivory torso of a toilet lay on the carpet. By now he smelled the sourness of a doused fire. In a third room, the window was covered by a blanket that Arkady pulled aside to let moonlight creep in. A box spring had been stripped to the coils and set over a hubcap as a makeshift grill and pan that was filled with coals and water and a ghostly hint of smoke. An open suitcase showed a toothbrush, cigarettes, fishing line, a can of beef and a plastic bottle of mineral water, a plumber's pipe cutter and a wrench wrapped in rags. If their owner had been able to resist a peek out of the blanket, Arkady never would have seen him. He spotted him now, moving at the edge of the plaza.

Arkady went down the stairs two at a time, sliding over an overturned desk, stumbling on the crushed maroon of hotel drapes. Sometimes he felt like a diver plunging through the depths of a sunken ship, his vision and hearing magnified in such faint light. As he hit the ground, he heard a screen door slap shut at the far end of the plaza. The school.

Between the school's two front doors was a blackboard that read APRIL 29, 1986. Arkady ran through a cloakroom painted with a princess and a hippo sailing a ship. The lower rooms were for early grades, with blackboard examples of penmanship, bright prints of farm children with happy cows that smiled amid blown-in windows and desks overturned like barricades. Footsteps pounded the floor above. As Arkady climbed the stairs, a display of children's art fluttered in his wake. Pictures of students sitting neatly in a music room led to a music room with a shattered piano and half-size chairs around broken drums and marimbas. Dust exploded with every step; Arkady swallowed a fine powder with every breath. In a nap room, bed frames stood at odd angles, as if caught in a wild dance. Picture books lay open: Uncle Ilyich visiting a snowy village, Swan Lake, May Day in Moscow. Arkady heard another door shut. He ran down a second stairway to the school's other exit and slowed to navigate a heap of child-size gas masks. Crates had been delivered and tipped over in a panic. The masks were shaped like sheep heads, with round eyes and rubbery tubes. Arkady burst out the door, too late. He played the flashlight around the plaza and saw nothing.

Although it was wrong to think "nothing" when the place was so alive with cesium, strontium, plutonium or pixies of a hundred different isotopes no larger than a microdot hiding here and there. A hot spot was just that: a spot. Very close, very dangerous. One step back made a great difference. The problem with, say, cesium was that it was microscopic-a flyspeck-and it was water-soluble and adhered to anything, especially the soles of shoes. Grass that grew chest-high from scams in the road earned another tick from the dosimeter. At the opposite end of the plaza from the school was a small amusement park, with crazy chairs, a rink of bumper cars and a Ferris wheel that stood against the night like a rotting decoration. The reading at the rink shot the needle off the dial and made the dosimeter sing.

Arkady made his way back to the hotel, to the room with the box-spring grill. He weighted, with the can of beef, a note with his mobile-phone number and the universal sign for dollars.