Murder is easy

Policeman Luke Fitzwilliam is on his way to London by train. As it often happens, he strikes up a conversation with his fellow traveler Miss Pinkerton, who is going to Scotland Yard to report a series of mysterious murders in the provincial town of Wychwood. Luke, of course, doesn't believe a word of it, considering the old woman just too emotional.
However, after some time he will have to change his mind, because he learns that almost immediately after Miss Pinkerton got off the train, she was hit by a car...
So Luke goes to Wychwood to investigate this case - not as simple as it seems at first glance.