Prompt: It seems to be constantly raining in London during the one week Holmes needs the weather to be clear. (YoughaltheJust)
I hope you'll forgive me for turning a week into a day and London into Edinburgh to fit the ongoing narrative while keeping to the spirit as best as I can.
We at last made our way downstairs and out onto the street to be greeted by a steady rain which showed no signs of letting up.
"The curse of our charming isle," Holmes remarked with equal parts humour and genuine displeasure. "I fear this will not aid in our investigation, but perhaps we may be able to glean something about Mr. Marcus despite it."
We set off into the rain, our coats drawn up tight and hats pulled low in an attempt to shield us from the worst of the weather. We were far from alone in hurrying down the grey streets through the rain and no less than three cabs passed us by before one saw us and deigned to stop, sending up waves of muddy runoff in its wake.
Holmes gave the driver the address with the impatience borne of discomfort—I felt hardly more charitable as the water soaked through my trousers—and we were off with due speed. The city passed behind an ever-falling veil to an endless symphony of pattering and splashing.
My trousers had not even begun to dry when we were let off in the midst of the mediaeval old town, in front of the very same tenement we had observed on our first night in the city. The cab splashed on its way as soon as our feet touched the cobblestone, and Holmes quickly drew me across the street to enter the address we had only watched from the outside before.
A young lady greeted us at the door, and with a brief explanation from Holmes, allowed us inside the modest flat. It was not so comfortable as our rooms at Baker Street, if in somewhat less disarray, bearing evidence of a workman's life and a woman's touch.
Holmes immediately set about his usual investigation, examining every inch and corner for the most minute detail, making quiet exclamations as he went. I could but wonder what it was that he observed with those remarkable, keen eyes, and I found I was more than content to watch and make some attempt at conversation with our hostess as I waited for my clothes to slowly dry by the small coal furnace.
I did not have long enough to wait, as Holmes completed his investigation as suddenly as he had begun and swept from the flat, drawing me with him. "I fear things may be more serious than we anticipated," was the only indication he gave of what he had observed.
From there we hurried through the rain once more. We did not stop to call a cab, and instead came to the entrance to a park, which consisted of a hill in the midst of the city. In more pleasant weather it would have made for a charming stroll, but in the rain the well-trodden paths had all turned to mud. Even Holmes did not linger, though his eyes were fixed upon the ground as we climbed, I am certain not only to keep his footing, but also to look for any indication of the reason for which we had come.
Our pace was not so fast, but my legs ached and my feet began to slip as we neared the summit. Holmes held out his hand to me, his glove soaked through, and helped pull me up the last few steps to the peak of the hill. As I stopped to rest my sore legs, he let out a barking laugh.
"I am afraid, Watson, my reason has failed us both and our errand has been in vain," he said. "We will not be able to see anything with this rain, on the ground or beyond."
He motioned out at the city and port around us, which must have been a sight to behold in more clement weather, but now we saw only faint grey shapes hidden behind a rainy curtain. The hilltop around us was a mostly bare expanse, which fell off sharply into a cliff a little ways beyond where we stood. However, peering through the rain, I thought I saw a rocky outcropping which rose up above us.
"Holmes," I said, "might that be some shelter, at least?"
Holmes followed my gaze and urged me toward it with a chuckle. "Excellent, Watson! I believe that is not a mere shelter, but the ruins of an ancient fort which once stood upon this hill."
We neared and it quickly became apparent that it was indeed not a natural outcropping of stone, but an arrangement of stone bricks into the remnants of an ancient wall, which provided little shelter from the rain.
"I fear even an archeological inquiry would be difficult in this rain," Holmes said, though I could detect some underlying chagrin at the defeat. "Shall we return to town to dry off and lunch and regroup?"
"That might be for the best," I said.
He took my arm in his and I gratefully clung to it—and he clung to me—as we began our cautious descent.