midnight
`` I sleep sound , sir , '' she answered , `` and I do n't think any ghosts will trouble me in the daytime . So thank you , sir ; I will bring over a few things and stay here , if you please . '' `` Very good ; here is the key of the back door , '' I answered ; and in five minutes more I was trudging Londonward . As I walked along I decided not to say anything to Mr. Craven concerning the previous night 's adventures ; first , because I felt reluctant to mention the apparition , and secondly , because instinct told me I should do better to keep my own counsel , and confide in no one , till I had obtained some clue to the mystery of that midnight watcher . `` Now here 's a very curious thing ! '' said Mr. Craven , after he had opened and read the letter left at River Hall that morning . `` This is from a man who has evidently not heard of Mr. Elmsdale 's death , and who writes to say how much he regrets having been obliged to leave England without paying his I O U held by my client .