I do not know if any person in the city could have done the thing except Dr Ming. But Dr Ming it was, there at the place and time we needed him, and with neither question nor even protest. Events proceeded as if they had been meticulously choreographed: Holmes' mouth going shut just as the old man was raising his head to shout; the revolver in Holmes' hand going off, pointing at the sky; the crowded street shuddering into attention, every head turned our way. The old man's voice seemed tiny in the wake of the shot, but his words acted like a spark set to a line of gunpowder. His command sputtered through the nearby pedestrians, then caught as each person turned and passed the phrase on, and on it ran up the street, fizzing and furious as it burned through the residents, coming even with the honking maroon bonnet, passing it, converting itself into motion: A heavy-laden greengrocer's cart began moving, slowly at first but inexorably into the path of Greenfield's stolen motor. The horn cut off as the Chrysler squealed one way then overcompensated to the other before smashing into the cart and a parked poultry lorry at the same moment. Cabbages and caged chickens rained down in all directions as the stunned pair tried to keep moving. Greenfield got so far as to raise his pistol, but the crowd had already closed over them, and the gun went off pointing at the upper window of the telephone exchange, causing a number of trunk calls to come to grief as their connexions were yanked free by startled operators.

We remained where we were while the community brought Dr Ming his two prisoners. The old man had settled down onto the emerald bonnet of our own stolen motor, his hands tucked together into invisible sleeves, and was in placid conversation with Holmes; Hammett gazed at the two of them in frank disbelief; I let myself out of the motor slowly, watching the procession come near.

Greenfield struggled against his bonds of grocer's twine, shouting furiously. His sister had her hands tied as well, and I looked at her carefully, wondering if I had seen her on board the Marguerite. She was a tall woman, nearly as tall as I, and although her suspiciously uniform brown hair was slightly mussed by the chase, otherwise she appeared so self-contained, she might have been pausing to answer the queries of a passer-by rather than waiting for the police. Studying her closely, I thought I might have seen her on the ship, perhaps on the night of the fancy-dress ball, but I would not have sworn to it. She came quietly in the hands of her captors, her expression more watchful than daunted; I thought the police needed to be warned that she should be carefully searched.

I wanted to talk to her, wanted in fact to grab her hard and demand what had set her on our heels so resolutely, but then I saw her glance at him, and in that one glance, it all became clear.