Poirot carefully straightened a china ornament on one of the bookcases. “Be sure there was a reason,” he said over his shoulder.

“But what reason could it be?”

“When we know that, we shall know everything. This case is very curious and very interesting.”

There was something almost indescribable in the way he said those last words. I felt that he was looking at the case from some peculiar angle of his own, and what he saw I could not tell.

He went to the window and stood there looking out.

“You say it was nine o’clock, Dr. Sheppard, when you met this stranger outside the gate?”

He asked the question without turning round.

“Yes,” I replied. “I heard the church clock chime the hour.”