A/N: Somewhat loose interpretation of the prompt (sorry!) and a piece that accompanies Chapter 8 of this series.

From mrspencil: a journey by rail ends in chaos

Holmes returns from Dublin frustrated. The case is solved, the client suitably impressed, and his pockets lined with twice the amount he was promised when the job was offered to him; but he knows he should have been faster. His thought processes were sluggish, hindered... The question of why is a sore tooth in an inflamed gum, one he probes at for the entire journey home.

It is a ship first, from Dublin to Liverpool, and then a train direct to King's Cross Station from there. He finds himself bored, yearning for company and grateful as he thinks of a warm fire back in Baker Street and a conversation with Watson. He finds he has missed the good Doctor's company, a fact which surprises him. He is by no means a sociable man, and he always used to prefer his own company above all others.

The solution to his problem presents itself just as he steps onto the platform of the station. Watson. Could that be what had affected his investigation in Ireland? If so, he is quite relieved. A simple problem with a simple solution, rectified in future by insisting on double the compensation for transport fares and accommodation when taking any cases that require travel. Watson, after all, is not yet back in active practice and has always shown an enthusiasm for Holmes's casework. He hails a cab to Baker Street with contentment.

This contentment starts to fade, however, as he enters 221B.

The flat is almost as cold as the street outside, meaning no fires have been lit for at least a day; Mrs Hudson is not here and, judging by the missing coat on the stand, Watson is gone too. In the kitchen, Holmes finds an open cookery book with a handwritten note from their landlady that highlights the easier recipes. She has done similar before, when visiting her sister, so that is one mystery solved.

The living room is as it ever was, save that a few of Watson's novels are missing from their shared bookcase. It is not enough of a clue to deduce where he has gone, but Holmes can see from the lack of dust that it was just two or three days ago that he left.

Finally, he goes to Watson's room. He is apprehensive to disturb his flatmate's privacy, but a strange knot of apprehension has formed in his stomach. As the door creaks open, this feeling resolves into outright dread. The room is in chaos.

The bed has been pushed to a diagonal angle, revealing a fresh scrape on the floor. Bits of old army uniform are scattered across the floor, as are several old, yellow-paged journals. The window has been left open and the chilly winter wind which blows through it has dislodged the contents of the journals and scattered them across the room. Old photographs, scribbled letters and other such debris rustles underfoot as Holmes goes to close the window, and begins to tidy away the mess.

Watson had left in a hurry, that much was obvious. He had pushed his bed aside and pulled out his only valise, scraping the floor in his haste and making no attempt to repair the damage. He removed his army uniform and old journals haphazardly, not even bothering to close his bedroom window as he packed. A quick glance in the wardrobe shows that he has taken his winter clothes with him.

Holmes frowns. It is unlike his flatmate to act so impulsively, particularly without leaving a note of his whereabouts. Watson's funds are low, so he would not have been able to travel far. As Holmes reaches this conclusion, a postcard on the floor catches his eye. The photograph is of Edinburgh Castle, and the writing on the back reads,

Dear J,

Best of luck in London.

-H

Holmes's frown deepens. The tone of the postcard is hardly a warm one, making it difficult to ascertain the nature of this person's relationship with Watson. It is dated from before Watson's time in the army - perhaps when he went to study medicine at Barts? Could this card be from a distant family member? Watson had once said to Holmes he did not have family in England, but he had never clarified if he had any in Scotland.

Holmes sighs and pockets the postcard. It is not much of a lead, but under the circumstances it is the best he can do. He had hoped for rest, but knows he will get none until he tracks down his missing flatmate. He returns to Kings Cross and books a seat on the next train to Edinburgh.