Ten minutes later I was at home once more. Caroline was full of curiosity to know why I had returned so early. I had to make up a slightly fictitious account of the evening in order to satisfy her, and I had an uneasy feeling that she saw through the transparent device.

At ten o’clock I rose, yawned, and suggested bed. Caroline acquiesced.

It was Friday night, and on Friday night I wind the clocks. I did it as usual, whilst Caroline satisfied herself that the servants had locked up the kitchen properly.

It was a quarter past ten as we went up the stairs. I had just reached the top when the telephone rang in the hall below.

“ Mrs. Bates,” said Caroline immediately.

“I’m afraid so,” I said ruefully.