“There’s a perfectly feasible explanation, I’m sure, Harry,” she said. “Perhaps it is some practical joke being played upon you and Mabel by your friends. They want you out in the South for a week or two to escape from the cold and wet of the London spring. I wouldn’t worry, if I were you.”

“Ah, Gwen!” I sighed. “You are unaware of all the grim circumstances,” I said. “There’s a serious conspiracy here, I’m convinced. The hand of a secret enemy has been lifted against me.”

Had that crafty servant at Sussex Place dispatched the false message, I wondered? Or was it Kirk himself? And if so, with what motive? Was Mabel, my beloved and devoted wife, to fall helplessly into their unscrupulous hands? My blood rose within me when I reflected how innocently I had walked into the trap which my mysterious neighbour had prepared for me.

I took up a Bradshaw, and saw that if I left Charing Cross by the boat-train at 2:20 I might, by good chance, catch the night mail for Italy by the Mont Cenis from the Gare de Lyon. I could only do it if we ran into the Gare du Nord in time. But from experience I knew that the afternoon service to Paris was pretty punctual, and one usually arrived in the French capital about 9:20. Then, by the aid of a taxi-cab, I could get across to the Lyons station in time.

So I decided to make the attempt. I had been in Italy several times when a youth, and knew Italian fairly well. My father, before the smash in his fortunes, had rented a villa for several years up at Vallombrosa, in the chestnut-clad mountains above Florence.

“May I come with you, Harry?” pleaded my sister-in-law. “If Mabel is in any danger it is only right that you should take me to her.”

I knew how devoted the girl was to her sister. A year ago she had come to us from Caen, where she had been at school, and among the languages in which she was proficient was Italian. I hardly cared, in the circumstances, to leave her alone; therefore, although a big hole must be made in my slender bank account, I resolved to take a second ticket for her.

When I announced my decision her dark eyes sparkled with delight, and she clapped her hands.

“You are a real good brother, Harry!” she cried. “I don’t want any breakfast. I’ll go and begin to pack at once. I’ve never been in Italy, you know.”

I told her that in the circumstances of the rush we must make across Paris I could only allow her hand-luggage, and she sped away upstairs to put on her frock and to commence placing her necessaries together.