Blackwater Station had five platforms in the ordinary world and six in the sort of world one mentioned only after checking the listener for signs of ridicule.

Platform Zero did not appear on the public map, the station wall chart, or the enamel sign by the ticket office that still listed excursion fares to places that had ceased to exist as administrative categories. It appeared instead at 11:58 on Thursdays, provided the signal box was unlocked, the westbound board was displaying a lie, and somebody carried paperwork with enough conviction.

Bertie handled the signal box key.

"Why do you have that?" Mabel asked as they crossed the footbridge.

"I do maintenance."

"Since when does maintenance include hidden rail platforms?"

"Since the council cut budgets and expanded impossibility."

The station below them was busy with lunchtime commuters, paper sacks of chips, and the sighing machinery of people trying not to miss connections. Rain silvered the rails. On platform three a conductor argued with a pigeon over a sandwich crust. Nothing about the scene suggested hidden time corridors, which Mabel found almost rude.

Inspector Vale kept pace at her side, though now and then a passerby drifted through his sleeve without noticing. He did not appear to mind.

"You met Mr. Spatchcock?" Mabel asked.

"Unfortunately. Deputy Town Clerk. Keeps his pens in ranked formation. Smiles like a man checking whether a drawer is locked."

"Do people generally steal time for profit?"

"Usually for convenience. Profit is merely convenience with invoices."

Mrs. Vale-Smythe, marching ahead in a hat severe enough to regulate traffic, called back, "Mr. Spatchcock has never been promoted as far as he feels destiny intended."

"That sounds dangerous."

"It is the foundation of local administration."

The signal box smelled of rust, damp wool, and old electricity. Bertie unlocked the side door and ushered them inside. Levers rose from the floor in painted ranks. A wall clock above the control board ticked with the kind of self-importance usually found in headmasters and geese.

On the far side of the room, half hidden by a tarpaulin, stood another door. It was narrow, green, and completely incompatible with the box's outer dimensions.

"You have got to stop producing doors," Mabel said.

"No one's producing them," said Bertie. "They've always been there. Most folk just choose not to notice."

Vale took the Thursday File from under his arm and held it up. The brass corner plates began to hum. Outside, the signal wires trembled. The wall clock struck noon.

The green door opened inward.

Platform Zero was waiting on the other side.

It was longer than the station should have allowed and quieter than any working railway had a right to be. Overhead, ironwork vanished into dim glass. The departure board showed destinations such as LAST WEEK, IF YOU INSIST, and RETURN SUBJECT TO CIRCUMSTANCES. At the platform edge stood a single bench, a brass luggage trolley, and a kiosk selling newspapers from confusing dates.

Behind the kiosk a man in a waistcoat was repairing a pocket watch under a yellow lamp.

He had silver hair, round spectacles, and the relaxed manner of someone who had seen much stranger visitors than four damp municipal employees and a dead detective.

"Ah," he said without looking up, "the clerical delegation."

Mabel approached with caution. "Are you the watchmaker?"

"Technically I am a horological mediator. But watchmaker fits better on receipts."

He set down the watch and offered a dry, oil-marked hand. "Ephraim Bell. Keeper of Blackwater's public timepieces, occasional repairman of causality."

"Mabel Quince."

"Yes, I know. You were here next Tuesday."

That sentence passed through Mabel's mind like a cold spoon.

"Did I say why?"

"You asked for a diagram, borrowed my red pencil, and ate three custard creams. I hope you found the diagram useful, because the biscuit situation was severe."

Vale leaned on the kiosk counter. "Ephraim, someone's rifling the Thursday reserves."

"I noticed. The west clock lost eleven minutes and started quoting railway poetry."

Mrs. Vale-Smythe laid the three recovered index cards before him. "Mr. Spatchcock has access to these notes. We need to know what he can do with the chronometer key."

Bell's genial face tightened.

"Too much," he said. "The chronometer doesn't send people through time. That's melodramatic. It redistributes slack. Spare minutes. Administrative drift. Delays no one noticed and early arrivals no one deserved. In careful hands it's a repair tool. In ambitious hands it becomes a hiding place."

"A hiding place for what?" Mabel asked.

Bell looked at her over his spectacles. "Whatever cannot survive scrutiny in the correct week."

He took down a ledger from behind the counter and opened it to a page crowded with little brass-ink notations. Mabel recognized the town's districts listed by clock tower, tram stop, and public office. Several entries had been circled.

Town Hall Committee Room B - 47 minutes unaccounted for.

Civic Treasury Corridor - recurring 12:14.

Mayor's Parlour - one luncheon duplicated, contents unclear.

Vale let out a quiet whistle. "He's been making pockets."

"Small ones," Bell said. "Too small for grand crimes. Perfect size for petty paperwork, missing receipts, or one very embarrassing afternoon."

Mabel thought of Mr. Spatchcock's immaculate cuffs, his ranked pens, and the typed note warning her not to let him handle the minutes.

"Then why steal whole Thursdays?" she asked.

"Because he made a mistake," said a new voice.

The newspaper kiosk girl had looked about sixteen when Mabel first noticed her. Now, standing straighter, she seemed older and younger by turns, like a photograph developing. She wore station blues from no railway Mabel knew.

"He's overdrawn," she continued. "Took more slack than the town could spare. The ledger is trying to collect."

Bell sighed. "Miss Harker minds the departures. She disapproves of amateurism."

"I disapprove of people putting committee work into the foundations of time," Miss Harker said. "It cheapens the whole enterprise."

Mabel stepped closer to the board. One line flashed, blanked, and then resolved into a destination:

TOWN HALL - NEXT WEEK'S MINUTES

"That can't be helpful," she said.

"On the contrary," Vale murmured. "Minutes are always where guilt goes to be alphabetized."

Bell shut the ledger.

"If you want your answers, Miss Quince, you need the chronometer chamber. Mr. Spatchcock will go there when he realizes the file is no longer lost. He'll think he can rebalance the books before anyone notices."

"And can he?"

"Oh yes," Bell said. "That is what makes him troublesome."

Bertie had wandered to the end of the platform, where a luggage trolley stood beneath a poster promising FAST COMFORTABLE REVISABLE TRAVEL. He lifted a tarpaulin and revealed a bicycle with a wicker basket on the handlebars.

"There's our transport," he said.

Mrs. Vale-Smythe stared. "We are not pursuing a temporal embezzler by bicycle."

"Not with that attitude," said Bertie.

Bell handed Mabel a flat brass key no bigger than a domino.

"Chronometer access. And take this."

He passed her the red pencil she had apparently not yet borrowed.

"What is it for?"

"Underlining revelations. Looking competent. The usual."

Miss Harker reached up and turned a little plate on the departure board. The letters clattered into place:

BOARD NOW - LIMITED STOPS TO NEXT THURSDAY

Vale smiled in a way Mabel had begun to associate with bad but unavoidable ideas.

"Well," he said. "Shall we go read the minutes?"