After less than a week Nurse Bosworth, employed to care for the two young sons of Mr and Mrs Francis M. Reed, becomes so nervous she leaves their employ. She believes a crime has been committed in the Reed's house in Beauregard Square. It's certainly an odd household -- she and the children are locked in at night, all the servants have been dismissed, the phone wires are cut, and the boys' parents are extremely jumpy and look positively ghastly.
Enter Nurse Hilda Adams, who occasionally assists the police with information discovered via her professional role. Sent by Detective Patton to replace her colleague, she finds the house to be just as described and so starts her investigation on what is going on. This comes to cover such conundrums as the "basement ghost" seen in houses in the square, where and why the boys' dog disappeared, and explanations for various strange events at night.
Eventually she solves these and associated matters such as the reason the boys' mother sleeps in a cot at the head of the stairs, why all the carpets and most of the furniture has been removed, and what forces the Reeds to keep their lights blazing all night.
My verdict: The clever unexpected solution to this multitude of mysteries explains all the strange events, yet it would likely not occur to most readers. There is a sort-of clue early on that might put them on the track to guessing what is taking place in the house, but I should have liked one or two more obvious pointers. The closing revelations certainly surprised me! More I shall not say about this tightly written and genuinely suspenseful novella for fear of revealing too much.