At nine minutes past nine on a damp Thursday morning, Mabel Quince opened the archive office and found tomorrow waiting in her in-tray.

It was folded twice, stamped MUNICIPAL INTERNAL in purple ink, and addressed to her in the severe typing style favored by people who thought friendliness led directly to mutiny. The paper was still warm. That would have been odd enough without the date.

Friday, 14 October.

Unfortunately for the memo, and for everyone else in Blackwater-on-Mere, it was still Thursday, 13 October, and had been for several hours.

Mabel held the page up to the window as if daylight might embarrass it into honesty.

"No good staring," said Bertie Pikes, the caretaker, as he came past with a mop, a kettle, and the expression of a man who expected floors to betray him. "Some documents are shameless."

Mabel handed him the memo. "Does that look like tomorrow to you?"

Bertie squinted. "Depends whether we’re charging overtime."

She took it back and read it again.

MISS QUINCE,

Do not allow the Thursday File to be removed from Sub-Basement Sector Nine at 11:17 a.m. If a man in a brown hat asks for Inspector Vale, tell him he is running early by six years.

Bring tea.

This matter is not yet urgent, but give it twenty-three minutes.

Regards,

M. Quince

Mabel sat down very carefully. There are moments in life when one hopes for an explanation involving a prank, a clerical slip, or carbon monoxide. A memo signed in your own name but written in a tone you had not yet achieved was not one of them.

"You've finally started managing yourself," Bertie said. "That's either ambition or collapse."

"Bertie, does the town hall officially have a Sub-Basement Sector Nine?"

"Officially? No. Unofficially, yes. We keep the things no committee wants to remember down there."

"And Inspector Vale?"

Bertie took the kettle off his trolley and considered the question with priestly solemnity.

"Retired detective. Drowned in the mere in 1988. Still comes by sometimes, depending on the weather."

Mabel waited for him to smile. Bertie, maddeningly, remained sincere.

"Still comes by."

"Only in the archive," he said. "Something to do with the clocks. Or guilt. Hard to say. Tea?"

She accepted tea because refusing it would have implied confidence.

By ten o'clock the memo had not become less impossible. It sat on her blotter with the composure of a thing that had every legal right to exist. Mabel tried the ordinary methods first. She checked the date on the wall calendar. Thursday. She checked the local newspaper. Thursday. She checked the biscuit tin for messages from the future. Empty, which felt like a personal attack.

At ten twenty-three the Chief Administrative Officer, Mrs. Cressida Vale-Smythe, swept into the archives with a folder clamped under one arm and crisis already selected as her mood for the day.

"Miss Quince, has anyone requested the Thursday File?"

Mabel blinked. "What is the Thursday File?"

Mrs. Vale-Smythe lowered her voice, which somehow made it sharper. "A ledger of municipal anomalies. Misdated meetings. Repeated afternoons. A regrettable incident in 1974 involving a brass band and seventeen minutes that occurred twice. It is not for casual circulation."

"Has someone asked for it?"

"Not yet," Mrs. Vale-Smythe said. "That is what concerns me."

She departed without elaboration, in the way senior officials often do when they believe mystery is an administrative skill.

Mabel looked at the memo again.

Not yet urgent, but give it twenty-three minutes.

At ten fifty-four she went downstairs.

The public levels of Blackwater Town Hall were respectable in the way of buildings that had been painted often enough to conceal doubt. The archive stairs, however, descended through successive decades of regret. The first landing smelled of dust. The second smelled of wet brick. The third smelled faintly of hot metal and old rain, which Mabel did not care for at all.

Sector Nine was at the end of a corridor that appeared not to have made up its mind about existing. A hand-painted sign pointed left and said RECORDS. Another pointed right and said NO, NOT THOSE RECORDS. Mabel chose left, because at least it sounded committed.

The room beyond was larger than it had any right to be. Shelves marched into dimness. Cardboard boxes sat in labeled rows: WATER RATES, TRAM PETITIONS, LOST SWANS, THINGS WE SHALL DENY. At the center, on a wheeled trolley, rested a slim black file with THURSDAY lettered on the spine in white paint.

Mabel checked her watch. 11:14.

Someone coughed politely behind her.

She turned and found a man in a brown hat standing in the doorway. He was tall, damp at the cuffs, and faintly translucent around the ears, which was not encouraging. He carried himself like a detective from an older, sterner age, though there was mud on one shoe and a daisy caught in his coat sleeve.

"Inspector Vale?" Mabel said before she could stop herself.

"On a temporary basis," he replied. "Have you got the file?"

"You're running early by six years."

He stopped dead. Then he looked at her, at the file, and at the corridor ceiling as if doing arithmetic against his will.

"Oh bother," he said. "We've crossed the streams again."

Mabel had expected many reactions from a dead policeman. Irritation was surprisingly grounding.

"I have a memo from tomorrow," she told him.

"Then you're the right Quince. Excellent. Tea?"

"The memo said to bring tea, not that I would have the chance."

"Pity. Temporal investigation is ninety percent hydration."

Another set of footsteps sounded in the corridor. Fast ones.

Inspector Vale's expression sharpened. "That will be our problem."

Mrs. Vale-Smythe appeared in the doorway, breathing hard. "Miss Quince, step away from that file."

"I haven't touched it."

"Very wise."

Vale tipped his hat. "Morning, Cressida. Still pretending not to believe in me?"

She did not so much as glance at him. "You are not scheduled until 1994."

"Yes, yes, I know. Ghastly inconvenience."

Mabel looked from one to the other. "Would anyone like to explain why the drowned detective and the chief administrator are fighting over a folder named after a weekday?"

Mrs. Vale-Smythe shut the door behind her. "No."

"I would," said Vale, "but she dislikes my tone."

"Inspector."

"Very well. Short version, Miss Quince: someone has been removing time from Thursdays and filing it elsewhere. We have lost three quarter-hours, one council luncheon, and the better part of a mayoral apology. If the Thursday File leaves this room before 11:17, the gaps become permanent."

Mabel stared. "That is not a short version. That is an indictment of reality."

"Reality is municipal," said Vale. "It survives mostly through paperwork."

At 11:16 the lights flickered. Shelves shivered with a sound like a thousand pages turning at once.

Then the trolley began to move.

No hand touched it. No wheel caught a stone. The Thursday File rolled by itself toward the back wall, where the air had developed a silvery crease like badly hung fabric.

"Oh, for heaven's sake," said Mrs. Vale-Smythe.

Vale lunged for the trolley. Mabel grabbed the kettle from Bertie's tray where she had left it outside the room, because when time misbehaves one must work with available tools. She sloshed tea across the floor in front of the moving wheels.

The trolley skidded. The file slid free, flew upward, and struck the brown-hatted inspector squarely in the chest.

The room went still.

From somewhere beyond the silvery crease, a voice called, very faintly, "Could someone send down my umbrella?"

Vale looked at the file in his hands and sighed.

"Well," he said. "Now it's urgent."