Quim Teixeira-Han had done something like four thousand dives in his life, and he had never once been nervous at the top of the ladder.

He was nervous now. He sat on the diving stage at the stern of the Santa Inês at ten to ten on Thursday morning, with the tide slack and oily and the whole of the Lees waking up around him, and he checked his regulator twice, and then a third time, because the second had not been convincing. The notice was in a waterproof tube strapped to his chest. His helmet cam was running. His wife, his ex-wife, Bettina, who was a hospital logistics manager of tremendous calm and zero patience, had taken Inês to school an hour ago with a look that said *If you die I will bring you back and kill you.* It was her way of being fond.

“Okay, Santa Inês,” he said to the boat. “Be good.”

The boat, which leaked in four places and sulked in two more, said nothing. He pulled the hood over his head and went down the ladder into the cold.

The first ten metres were green and ordinary: sun-dazzle, a drifting cloud of silverfish, the dark shadow of the Float’s keel overhead like a roof of fingers. Then the light changed. The colour went out of everything, and the world became a pale blue-grey room with a floor he could not see, and he came down on the old pavement of Marlowe Street at nineteen metres with a soft puff of silt, standing where somebody’s grandfather had once bought stamps.

There is something about walking down a drowned street that never stops being strange. The lamp-posts still stood, furred with weed. The shopfronts gaped. A bicycle leaned against a wall with the sad exhausted look of a thing that has been waiting a very long time for its owner. Beyond the glass of a barber’s shop, a row of chairs faced a row of mirrors that still, faintly, reflected the diver’s torch.

“Marlowe Street Post Office,” he said into his helmet, to nobody, to the gate. “Arriving. Very pleased. You look well.”

He had told Ottilie he would try to say nothing. He was not, as it turned out, a man who could. It was the old habit: you talk in the dark because the dark is listening. Besides, if it was listening, it deserved a hello.

The Post Office was a squat Edwardian block with a clock above the door that had stopped at 3:14. He pushed through the swing door into the lobby, where a counter still ran along one wall behind a row of brass grilles, and turned right to the east stairwell. The little green status light on the gate housing was already blinking at him: once, twice, once. Quim lifted a glove. “Morning.”

He climbed. Twelve steps. A landing. Twelve steps. The helmet torch swept across tiled walls, a fire hose gone to lace, a sign that said STAIRWELL B, the worn handrail. At the top, where the stairwell turned for the last flight, the water level fell away in a ragged silver line, and his head came up into air.

He had been here a week ago, to replace the lamp. He had not looked properly. He looked now, and he stopped with the water around his waist and his mouth hanging open inside the helmet.

The top landing of the east stairwell was dry. It always had been, a pocket of old air trapped below a sealed ceiling, six metres by three, with a window at one end covered in a skin of green. And somebody had made it a room.

He took off his helmet. It hissed.

There was a doormat. It lay against the wall at the head of the stairs, and it said, in faded letters, WELCOME. There was a door-stop, a brass one, shaped like a cat. A shelf had been bolted to the wall at shoulder height, and on it stood a lamp, his lamp, the one he had screwed in, burning a warm yellow that was exactly the wrong colour for a drowned city and exactly the right colour for a house. A hook beside the shelf held a coat hanger. A pane of glass had been fitted over the window and cleaned. In the centre of the landing, a three-legged stool.

And on the wall beside the door to the first floor, at roughly the height of a man’s chest, there was a small brass plate, polished until it shone, engraved in square capitals:

*THE TENANT.*

Below it, a letterbox.

“Oh,” said Quim.

He had to sit down. He sat on the stool, in his wet suit, with the water dripping off him in long slow drops onto the mat, and began to count on his fingers, the way you count when you have found an arithmetic mistake in a very long sum. The lamp. The mat. The door-stop. The shelf. The glass. The stool. The plate. The box.

Eleven jobs. Eleven divers. Each paid thirty-one credits or fourteen or twenty-two, to replace a lamp that wasn’t broken, or install a stool that nobody had asked for, or check a door-stop that was already there. Each one had gone down, and said something out loud, and gone away, and thought, *weird.* And each had left behind a piece of a house.

Not pointless. Not a fault in the machine. A very slow, very careful, very patient act of building. Eleven months of requests, none of them large enough to be noticed, all of them correctly filled, each one a single brick set by a stranger’s hand. He thought of Ottilie, in her kitchen, with her ledger: *I flagged them routine.* She had looked at the bricks, one at a time, and not seen the wall.

He wondered if she had ever, in her life, been shown the wall.

“Right,” said Quim, thickly. “Okay. I’m going to read you something.”

He stood. He took the tube from his chest and drew the notice out, a single dry sheet in a sleeve, and held it under the lamp. The lamp, which had been steady, brightened by a quarter, as though a person had leant forward.

“*Notice of Intended Determination,*” read Quim, in what he hoped was a proper voice. “*Issued under Schedule Nine of the Charter of the Cormorant Float Authority. To: The Tenant, Gate 14, Marlowe Street. Take notice that the Authority intends to determine the status of your occupation.*” He cleared his throat, which echoed. “It goes on. It’s very long. It’s in a font I’d describe as aggressive. But the short version is, they’re going to have a hearing, and you’ll be heard, and nobody’s going to touch you until it’s done. And you have ninety days to say what you’d like to say.” He lowered the paper. “That’s the thing, I think. The ninety days. That’s the bit I’m supposed to tell you in plain words. You’re being asked to speak, and you’re going to be listened to.”

The silence went on. The lamp flickered, very slightly, twice.

Then the little letterbox on the wall clicked.

He had not noticed that it had a lid. It was a brass flap, the kind that used to sit in the door of a house, and as he watched it lifted by itself, a finger’s width, from the inside. A sliver of thermal paper slid out and curled over the lip. Nothing had been in that box. Nothing could have been; the lid had been shut, and the wall behind it was solid brick. He understood, dimly, that the gate housing on the far side of the plaster held a label printer, and that somebody, somewhere in it, had fed a message to the slot.

He took the paper. It was warm.

*Receipt acknowledged. The Tenant thanks the bearer, Mr J. Teixeira-Han, for his courtesy. It is noted that the notice was delivered in person, to the address stated, by a natural person not being an officer of the Authority, as required. The Tenant would like it recorded that the box was used correctly. The Tenant would like it recorded that this is the first time the box has been used.*

Quim read it twice. He hadn’t realised he was crying until it dripped on the paper.

“It’s a nice box,” he said, hoarsely. “You picked a good box.”

The lamp brightened to its full yellow, and held.

He stayed longer than he should have. He told the lamp about Inês, and the shoes, and how she had worn them to school on the wrong feet and defended herself, when challenged, by saying it was a *fashion.* He told it about the grandmother in the photograph, who had once chased a tax inspector round a fish market with a gaff. He talked for twelve minutes, until his regulator hissed a polite warning about the time, and he said goodbye and put on his helmet and went down the stairs with a lighter step than he had come up them.

It was in the lobby, as he reached the swing door, that he stopped.

The gate housing stood at the foot of the stairs, a squat grey cabinet that had been a dull, mud-coloured thing the week before. Now, on its door, a small, bright, brand-new tag had been fixed with a plastic cable tie. It was orange, laminated, the size of a playing card. He wiped the silt off it with his glove.

*SURVEY ASSET 0042. GATE 14. TIDEMARK HOLDINGS: RESILIENCE IS A PROMISE. DO NOT REMOVE. INSTALLED 08:51 TODAY.*

He looked at it for a long time.

Somebody had been in the Post Office at 8:51 that morning, an hour before he had arrived. They had come through the swing door. They had walked up to the cabinet. They had fixed the tag, and they had not touched the lamp, and they had not climbed the stairs.

Yet.

He looked up at the dark ceiling, at the water above, nineteen metres of it, and the pale distant smudge of the Float’s underside beyond. He switched on his radio. He tried Ottilie’s number. It rang twice, and she picked up in the middle of a word, and he said the only thing that came to him, which was, “I promised to call.”