Moist swallowed, but gripped the banister. He climbed. There was a door on the first floor. It opened easily. It burst open at the mere touch of the handle, spilling pent-up mail out into the stairwell like some leaping monster. Moist swayed and whimpered as the letters slithered past him, shoal after shoal, and cascaded down the stairs. Woodenly, he climbed up another flight, and found another dimly lit door, but this time he stood to one side as he opened it. The force of the letters still rammed it against his legs, and the noise of the dead letters was a dry whispering as they poured away into the gloom. Like bats, perhaps. This whole building full of dead letters, whispering to one another in the dark as a man fell to his death— Any more of this and he'd end up like Groat, mad as a spoon. But there was more to this place. Somewhere there had to be a door— His head was all over the wall . . . Look, he said to his imagination, if this is how you're going to behave, I shan't bring you again. But, with its usual treachery, it went on working. He'd never, ever, laid a finger on anyone. He'd always run rather than fight. And murder, now, surely murder was an absolute? You couldn't commit 0.021 of a murder, could you? But Pump seemed to think you could murder with a ruler. Okay, perhaps somewhere downstream people were . . . inconvenienced by a crime, but . . . what about bankers, landlords, even barmen? 'Here's your double brandy, sir, and I've 0.0003 killed you'? Everything everyone did affected everyone, sooner or later. Besides, a lot of his crimes weren't even crimes. Take the ring trick, now. He never said it was a diamond ring. Besides, it was depressing how quickly honest citizens warmed to an opportunity to take advantage of a poor benighted traveller. It could ruin a man's faith in human nature, if he had one. Besides . . . The third floor yielded another avalanche of letters, but when they subsided there was still a wall of paper plugging the corridor beyond. One or two rustling envelopes fell out, threatening a further fall as Moist advanced. In fact it was retreat that was at the top of his mind, but the stairs were now layered with sliding envelopes and this was not the time to learn dry-slope skiing. Well, the fifth floor would have to be clear, wouldn't it? How else could Sideburn have got to the stairs in order to meet his appointment with eternity? And, yes, there was still a piece of black and yellow rope on the fourth-floor landing, on a drift of letters. The Watch had been here. Nevertheless, Moist opened the door with care, as a watchman must have done. One or two letters fell out, but the main slide had already taken place. A few feet beyond there was the familiar wall of letters, packed as tight as rock strata. A watchman had been in here, too. Someone had tried to break through the wordface, and Moist could see the hole. They'd put in their arm, full length, just as Moist was doing. Just like his, their fingertips had brushed against yet more compacted envelopes. No one had got on to the stairs here. They would have had to walk through a wall of envelopes at least six feet thick . . . There was one more flight. Moist climbed the stairs, cautiously, and was halfway up when he heard the slide begin, below him. He must have disturbed the wall of letters on the floor below, somehow. It was emerging from the corridor with the unstoppability of a glacier. As the leading edge reached the stairwell, chunks of mail broke off and plunged into the depths. Far below, wood creaked and snapped. The stairway shivered. Moist ran up the last few steps to the fifth floor, grabbed the door there, pulled it open and hung on as another mailslide poured past him. Everything was shaking now. There was a sudden crack as the rest of the staircase gave way and left Moist swinging from the handle, letters brushing past.

He swung there, eyes shut, until the noise and movement had more or less died away, although there was still the occasional creak from below. The stairs had gone. With great care, Moist brought his feet up until he could feel the edge of the new corridor. Without doing anything so provocative as breathing, he changed his grip on the door so that now he had hold of the handle on both sides. Slowly, he walked his heels through the drift of letters on the corridor floor, thus pulling the door closed, while at the same time getting both hands on to the inner handle. Then he took a deep breath of the stale, dry air, scrabbled madly with his feet, bent his body like a hooked salmon and ended up with just enough of himself on the corridor floor to prevent a fall through sixty feet of letters and broken woodwork. Barely thinking, he unhooked the lamp from the doorpost and turned to survey the task ahead. The corridor was brightly lit, richly carpeted and completely free of mail. Moist stared. There had been letters in there, wedged tight from floor to ceiling. He'd seen them, and felt them fall past him into the stairwell. They hadn't been a hallucination; they'd been solid, musty, dusty and real. To believe anything else now would be madness. He turned back to look at the wreckage of the stairs and saw no doorway, no stairs. The carpeted floor extended all the way to the far wall. Moist realized that there had to be an explanation for this, but the only one he could think of now was: it's strange. He reached down gingerly to touch the carpet where the stairwell should be, and felt a chill on his fingertips as they passed through it. And he wondered: did one of the other new postmasters stand here, just where I am? And did he walk out over what looked like solid floor and end up rolling down five flights of pain? Moist inched his way along the corridor in the opposite direction, and sound began to grow. It was vague and generalized, the noise of a big building hard at work, shouts, conversations, the rattle of machinery, the crowded susurrus of a thousand voices and wheels and footfalls and stampings and scribblings and slammings all woven together in a huge space to become the pure audible texture of commerce. The corridor opened out ahead of him, where it met a T-junction. The noise was coming from the brightly lit space beyond. Moist walked towards the shining brass railing of the balcony ahead— —and stopped. All right, the brain has been carried all the way up here at great expense; now it's time for it to do some work. The hall of the Post Office was a dark cavern filled with mountains of mail. There were no balconies, no shining brasswork, no bustling staff and as sure as hell there were no customers. The only time the Post Office could have looked like this was in the past, yes? There was balconies, sir, all round the big hall on every floor, made of iron, like lace! But they weren't in the present, not in the here and now. But he wasn't in the past, not exactly. His fingers had felt a stairwell when his eyes had seen carpeted floor. Moist decided that he was standing in the here and now but seeing in the here and then. Of course, you'd have to be mad to believe it, but this was the Post Office. Poor Mr Sideburn had stepped out on to a floor that wasn't there any more. Moist stopped before stepping out on to the balcony, reached down, and felt the chill on his fingertips once again as they went through the carpet. Who was it - oh, yes, Mr Mutable. He'd stood here, rushed to look down and— —smack, sir, smack on to the marble. Moist stood up carefully, steadied himself against the wall, and peered gingerly into the big hall.

Chandeliers hung from the ceiling, but they were unlit because sunlight was pouring through the sparkling dome on to a scene innocent of pigeon droppings but alive with people, scuttling across the chequerboard floor or hard at work behind the long polished counters made of rare wood, my dad said. Moist stood and stared. It was a scene made up of a hundred purposeful activities that fused happily into a great anarchy. Below him big wire baskets on wheels were being manhandled across the floor, sacks of letters were being tipped on moving belts, clerks were feverishly filling the pigeon-holes. It was a machine, made of people, sir, you should've seen it! Away to Moist's left, at the far end of the hall, was a golden statue three or four times life size. It was of a slim young man, obviously a god, wearing nothing more than a hat with wings on, sandals with wings on and - Moist squinted - a fig leaf with wings on? He'd been caught by the sculptor as he was about to leap into the air, carrying an envelope and wearing an expression of noble purpose. It dominated the hall. It wasn't there in the present day; the dais was unoccupied. If the counters and the chandeliers had gone, a statue that even looked like gold must've stood no chance. It had probably been The Spirit of the Post, or something. Meanwhile, the mail down there was moving more prosaically. Right under the dome was a clock with a face pointing in each of the four directions. As Moist watched it, the big hand clanked to the top of the hour. A horn blew. The frantic ballet ceased as, somewhere below Moist, some doors opened and two lines of men in the uniforms, sir, royal blue with brass buttons! You should've seen them! marched into the hall in two lines and stood to attention in front of the big doors. A large man, in a rather grander version of the uniform and with a face like toothache, was waiting there for them; he wore a large hourglass hanging in a gimballed brass cage at his belt, and he looked at the waiting men as if he had seen worse sights but not often and even then only on the soles of his enormous boots. He held up the hourglass with an air of evil satisfaction, and took a deep breath before roaring: 'Numbahhh Four Delivereeee . . . stand!' The words reached Moist's ears slightly muffled, as though he was hearing them through cardboard. The postmen, already at attention, contrived to look even more alert. The big man glared at them and took another huge gulp of air. 'Numbahhh Four Delivereeee wait for it, wait for it! . . . DELIVAAAAAAAH!' The two lines marched past him and out into the day. Once, we were postmen . . . I've got to find a real stairway, Moist thought, pushing himself away from the edge. I'm . . . hallucinating the past. But I'm standing in the present. It's like sleepwalking. I don't want to walk out on to fresh air and end up as one more chalk outline. He turned round, and someone walked right through him. The sensation was unpleasant, like a sudden snap of fever. But that wasn't the worst part. The worst part is seeing someone's head walk through yours. The view is mostly grey, with traces of red and hollow hints of sinus. You would not wish to know about the eyeballs. . . . face all contorted like he'd seen a ghost . . . Moist's stomach heaved, and as he turned with his hand over his mouth he saw a young postman looking in his general direction with a look of horror that probably reflected the one on the unseen Moist's face. Then the boy shivered, and hurried away. So Mr Ignavia had got this far, too. He'd been smart enough to work out the floor but seeing another head going through your own, well, that could take you the wrong way . . . Moist ran after the boy. Up here, he was lost; he must have toured less than a tenth of the building with Groat, the way constantly being blocked by glaciers of mail. There were other stairs, he knew, and they still existed in the present. Ground level, that was the goal: a floor you could rely

on. The boy went through a door and into what looked like a room full of parcels, but Moist could see an open doorway at the far end, and a hint of banister. He speeded up, and the floor disappeared from under his feet. The light vanished. He was briefly and horribly aware of dry letters all around him, falling with him. He landed on more letters, choking as dry, ancient mail piled up about him. For a moment, through the rain of paper, he caught a glimpse of a dusty window half covered with letters, and then he was submerged again. The heap under him began to move, slipping down and sideways. There was the crack of what could have been a door being burst off its hinges and the sideways flow increased noticeably. He struck out madly for the surface in time for his head to hit the top of a door jamb and then the current dragged him under. Helpless now, tumbling in the river of paper, Moist dimly felt the jolt as a floor gave way. The mail poured through, taking him with it and slamming him into another drift of envelopes. Sight disappeared as thousands of letters thudded down on top of him, and then sound died, too. Darkness and silence squeezed him in a fist. Moist von Lipwig knelt with his head resting on his arms. There was air here but it was warm and stale and wouldn't last long. He couldn't move more than a finger. He could die here. He would die here. There must be tons of mail around him. 'I commend my soul to any god who can find it,' he mumbled, in the stifling air. A line of blue danced across his inner vision. It was handwriting. But it spoke. 'Dear Mother, I have arived safely and found good lodgings at . . . . The voice sounded like a country boy but it had a . . . a scritchy quality to it. If a letter could talk, it would sound like that. The words rambled on, the characters curving and slanting awkwardly under the pen of a reluctant writer— —and as it ran on another line also began to write across the dark, crisply and neatly: Dear Sir, I have the honour to inform you that I am the sole executer of the estate of the late Sir Davie Thrill, of The Manor, Mixed Blessings, and it appears that you are the sole . . . .' The voice continued in words so clipped that you could hear the shelves full of legal books behind the desk, but a third line was beginning. Dear Mrs Clarck, I much regret to inform you that in an engagement with the enemy yesterday your husband, C. Clark, fought valiantly but was . . . And then they all wrote at once. Voices in their dozens, their hundreds, their thousands, filled his ears and squiggled across his inner vision. They didn't shout, they just unrolled the words until his head was full of sound, which formed new words, just as all the instruments of an orchestra tinkle and scrape and blast to produce one climax— Moist tried to scream, but envelopes filled his mouth. And then a hand closed on his leg and he was in the air and upside down. 'Ah, Mr Lipvig!' boomed the voice of Mr Pump. 'You Have Been Exploring! Welcome To Your New Office!'