I have a lot of problems with this book. And there are probably some spoilers that almost have to show up to explain the problems.
Briefly, the story. After a dinner party (of ill-assorted guests), the Earl of Selchester and his son Tom have a blazing argument, and Tom storms out. A blizzard subsequently blankets the castle and the countryside, and Lord Selchester is nowhere to be found the following morning. He is generally thought to be dead, but with no body, British law doesn't allow for a quick decision about this.
Fast forward to 1952 (?). Hugh Hawksworth, an intelligence agent who suffered a severe (but not well-described) leg injury) has been assigned to duties in the village in which the death or disappearance occurred. Shortly after he arrives, workers trying to repair a plumbing leak remove some flagstones and find--you guessed it--the Earl's body. After a very perfunctory investigation, both the locals and Scotland Yard are content to conclude that the son (Tom) returned to the castle, killed the old man, and buried him...and then left again.
Now, think about this. It would have taken hours to remove the flagstones and bury the body and replace the flagstons so that no one notices they've been disturbed (to say nothing of the likelihood that his decomposition might have been noticed), even if his sister (his presumed accomplice) had helped. And then he left...in his car? With the roads impassable? On foot? Through waist-high snow, without leaving a trace? Really? I rather doubt it. (I should add that Tom subsequently died in a fire-fight in Palestine.) Anyway, Hugo decides (for reasons that remain obscure to me) to poke around, and, of course, discovers THE TRUTH.
It helped that I was able to get this as a freebie (Amazon Prime), so at least I don’t feel that I overpaid for it…by much, at any rate. Also, and perhaps oddly, the title is never explicitly explained. Although we can all make up our own explanations of who the man in question is.