Prompt from mrspencil: a little old lady is not as she seems

I felt a tugging on my sleeve, and looked down to see a little old lady smiling sweetly at me. "Excuse me, sir, would you be able to help me?"

She was wearing an older style of dress with a shawl over it, draped around her wizened shoulders. What hair I could see under her bonnet was grey, though pinned back nicely In her arms she carried a shopping bag, one which looked much too heavy for her by the way she was hunched over it.

"Of course, madame. Would you like me to take your bag?" I held out my arm to take it from her, but she drew back.

"No thank you, sir, I'm well able to manage. Please, would you follow me?" She started walking towards a darkened alley branching off from the street. I hesitated, but she turned back to look at me and I couldn't help but follow. What harm could a little old lady be?

We turned down the alley, and the sounds of the London crowds died out behind us. The further we went, the darker the alley became, and the more I wondered if I had made a mistake. Finally, the old woman stopped, turning to one of the doors along the alley and drawing a key from her purse with a shaking hand.

"Please, madame, what do you need help with?" I had followed her so far, but I would not let her lead me further until I knew what I was dealing with. These back alleys could be dangerous, and I knew that some thieves would use any trick to draw a passerby into a trap.

"Just follow me, Watson." My friend's familiar voice startled me, and as I watched, the old lady straightened up, rising to Holmes' height for just a moment before regaining the old lady's hunch. "Please, good sir?" he said in the old lady's voice. Now that I knew where to look, I could recognise Holmes through the disguise.

"Of course," I answered, and followed him inside. Whatever his disguise or reasoning, I would follow Holmes anywhere.