It happened so fast, he panicked and ran home taking a shorter route, and beat you to the house, where he jumped into the bath so that no one would see him wet from the river. That is where you found him.

Of course, his story later was that you had left Rose alone and that is why she drowned.

While her death was not your fault, neither was it his, but he allowed you, John, to take the blame. Harry is fourteen now, at the time of this writing, and yet I already see his future. There is a flaw in his character, dearest son, like a vein of poison that runs in my family, but which has not touched you. Even at fourteen, Harry is troubled with drink. He thinks me blind to this.

I made a difficult decision. Knowing that you could shoulder the guilt better than your weaker brother, I delayed imparting this story to you until now, when you could, as an adult, make a choice – to confront your errant but fragile sibling or, knowing the truth, to spare him the confrontation and to move on.

And so I decided on this box, and this secrecy. I pray that Elspeth remembers to give it to you, and the hint about ‘your mother’s clock’. In this way, I knew no one but you could ever open it.

And the final thing, John, is my wish for you. You have nerve and courage, dearest son, and are destined for great things.

I glanced over at my sleeping friend. He had not read this and yet he intuited this assessment by a woman he had never met. I turned back to the letter.

I know you will grow to be a man of honour and accomplishment. I pray that you find a quest worthy of your gifts, my son, and that you take comfort and pride in lending your courage to that cause, that ideal, or that person. Then, looking down, I shall be happy for you.

You have it in you to be a force for good, John. The world needs you.

Your loving mother,

Mairead

I held the pages in my hands as my vision blurred for a moment. Her words sadly presaged my brother Harry’s alcoholism and early demise. And I thought it more likely that she had overstated her hopes for me, as parents do. Did the world really need John Watson?

I folded up my mother’s letter and my heart swelled. Had she really seen such promise in my young character? Perhaps any good deed I had done was in compensation for my regrets over Rose’s death. Suffering needlessly, as it turned out. I looked over at my friend, pale with exhaustion and asleep on the settee. Was this not like Holmes, suffering over his inability to save Odelia Wyndham?