The Mysterious Affair at Styles (Hercule Poirot Series)

I had been invalided home from the Front; and, after spending some months in a rather depressing Convalescent Home, was given a month's sick leave. Having no near relations or friends, I was trying to make up my mind what to do, when I ran across John Cavendish. I had seen very little of him for some years. Indeed, I had never known him particularly well. He was a good fifteen years my senior, for one thing, though he hardly looked his forty-five years. As a boy, though, I had often stayed at Styles, his mother's place in Essex.