The evening had been a pleasant one and I was humming quietly to myself as I left my club. There was not a cab to be seen that was not engaged, but the evening was quite fine - despite the snow that hung in the air - and I did not object to walking.
It was not until I had turned onto Baker Street that I reached inside the pocket that would usually hold my keys and discovered it to be empty.
Naturally, I knew some moments of panic, in which I searched every pocket with the same result. Knowing not what else to do - for the servants would all be in bed, at the top of the house, at such an hour and Holmes had been away on business for several days - I decided to retrace my steps. Could I have dropped them somewhere, quite close by?
I had not been walking for long when I realised my efforts to be made in vain, for the snow was deep enough to conceal a set of dropped keys and there was not enough light to see by, anyhow. All the same, I continued on my way in the hope that I might meet with someone from my club, who might have been able to offer me a bed for the night.
Of course, the club was dark when I reached it - empty and locked up for the night. There was nobody at hand to tell me whether I might have somehow left my keys on a table, or if perhaps they had fallen from my pocket when I had hung up my coat on the rack.
With a shiver, I set off again. On this occasion I had no direction at all and I was becoming too cold to think clearly.
"Doctor Watson!" a familiar voice called out suddenly, causing me to turn to look back in the direction from which I had just come.
A young constable, whom I had encountered once or twice, whilst working with Holmes, approached me at a run.
"Doctor Watson! I thought that it was you. Are you all right, sir? You looked so cold when you passed by me, just now, that I thought you might like a warming drink."
I thanked him and permitted him to lead me back to the sheltered spot in which he had been passing an uneventful and lonely shift.
"It's good to have some company," the fellow admitted as he poured me a drink from his flask. "This weather, only the worst criminals venture out - these shifts have a way of fast becoming tedious."
"I am very fortunate to have been noticed by you," said I, as I sipped from the cap of his flask gratefully. "I was becoming rather too chilled to go on for much longer."
"But what are you doing out, at this time? Were you looking for Mr Holmes?"
To my embarrassment, I found myself explaining my predicament to the Police official, who listened sympathetically.
"Well," said he at length. "I don't know where Mr Holmes is, or how we might reach him. But I do know that Inspector Lestrade lives quite near here - he's offered me a bed for the night, in a moment of need, and I'm sure he'd show the same kindness to you."
I thanked him, but I had no intention of becoming a bother and knocking the inspector up at such an hour.
"I'll come along with you," the chap announced. "I need to start on my rounds again, anyway."
I had never visited Lestrade's home before. Somehow, I felt that it suited him, for it was modest but comfortable, having been decorated with functionality in mind above all else.
The inspector showed me in and took me through to his parlour, leaving his constable to continue with his rounds. I was quickly given a pair of slippers for my chilled feet and a seat before a warming fire.
"You must stay here for the night," Lestrade insisted. "We'll have to see about finding your keys in the morning."
I thanked him and then yawned.
"Yes, you must stay here," the inspector repeated. "Once you're warmed through, I'll show you up to the guest room."
The guest room was small, but clean and presentable, with fresh linens on the bed and a basin of hot water awaiting me on the washstand.
The nightshirt that Lestrade had laid out for me at the end of the bed was much too small for me, so I instead pulled on the dressing gown provided, leaving my wet clothing set out in front of the fire, before scrambling gratefully between the sheets.
Thank God for good friends, I thought, as I fell to sleep.