“‘Mah and Micah,'” Mr Long repeated with a faraway look on his face. “I had forgotten that. They adopted me when I was seven years old, and my mother died. As it happened, I was their only child. Their actual names were Mai Long Kwo and Mah Long Wan. They worked for your parents as gardener and cook, beginning in 1902. I did not know your mother had a photograph of them on her bureau. I suppose I should not have been surprised, for this was one of the few things my mother saved from the Fire, and it resided near the place she had her house gods.” He drew from his inner coat pocket a portrait in a simple black wooden mounting, handing it to me. Smaller and set in a different frame, it was otherwise the same family portrait that lay buried in a drawer in Sussex: tall, blond American father, a secret smile under his trim moustaches; smaller, darker English mother, her eyes dancing as if she was about to burst into laughter; lanky blonde twelve-year-old with smudged spectacles, every inch of her shouting her impatience with the entire exercise; intense, dark-haired boy of perhaps seven, looking at the camera as if he intended to pull it apart to see how it worked.

I handed it back to him. “Where are your parents now?”

“They are dead.” He put the photograph into his pocket, seeming to spend considerable attention getting it settled, then raised his face to mine. “Murdered.”

A tingle of shock ran down my legs, and I was aware of Holmes coming to point, the pipe frozen in his hand.

“Tell us,” I said.

“It was during the New Year celebrations of 1915—our New Year, not that of the West, which is some weeks earlier. I was not here. I was at medical school in Chicago, and Western universities do not recognise the celebrations of other calendars. They were both in the store—but I should explain first.

“The previous spring, your parents had made them a loan of money to start a business. My father had begun to find the physical demands of gardening increasingly difficult, and when he admitted as much to your mother, instead of merely dismissing him as most people in her situation would have done, she asked him what he intended to do. He trusted her enough to tell her his dream of running a bookstore, although their savings would mean they would begin with little more than a cart on the street. Medical school is expensive. But your mother would not hear of it, and insisted that they find a space large enough for a proper store, and that they could repay her over time.”