A World War I tale of espionage in a fictional "backwater" area in England with no apparent military value called Dreymarsh. The story begins with Dreymarsh residents discovering an observation car from a German zeppelin along with a Homburg hat near Dreymarsh. This discovery triggers a range of events and introduces a myriad of characters which all make for a rather delightful mystery."Never heard a sound," the younger of the afternoon callers admitted, getting rid of his empty cup and leaning forward in his low chair. "No more tea, thank you, Miss Fairclough. Done splendidly, thanks. No, I went to bed last night soon after eleven-the Colonel had been route marching us all off our legs-and I never awoke until reveille this morning. Sleep of the just, and all that sort of thing, but a jolly sell, all the same! You hear anything of it, sir?" he asked, turning to his companion, who was seated a few feet away.Captain Griffiths shook his head. He was a man considerably older than his questioner, with long, nervous face, and thick black hair streaked with grey. His fingers were bony, his complexion, for a soldier, curiously sallow, and notwithstanding his height, which was considerable, he was awkward, at times almost uncouth. His voice was hard and unsympathetic, and his contributions to the tea-table talk had been almost negligible."I was up until two o'clock, as it happened," he replied, "but I knew nothing about the matter until it was brought to my notice officially."Helen Fairclough, who was doing the honours for Lady Cranston, her absent hostess, assumed the slight air of superiority to which the circumstances of the case entitled her."I heard it distinctly," she declared; "in fact it woke me up. I hung out of the window, and I could hear the engine just as plainly as though it were over the golf links."The young subaltern sighed."Rotten luck I have with these things," he confided. "That's three times they've been over, and I've neither heard nor seen one. This time they say that it had the narrowest shave on earth of coming down. Of course, you've heard of the observation car found on Dutchman's Common this morning?"The girl assented."Did you see it?" she enquired."Not a chance," was the gloomy reply. "It was put on two covered trucks and sent up to London by the first train. Captain Griffiths can tell you what it was like, I dare say. You were down there, weren't you, sir?""I superintended its removal," the latter informed them. "It was a very uninteresting affair.""Any bombs in it?" Helen asked."Not a sign of one. Just a hard seat, two sets of field-glasses and a telephone. It seems to have got caught in some trees and been dragged off.""How exciting!" the girl murmured. "I suppose there wasn't any one in it?"Griffiths shook his head."I believe," he explained, "that these observation cars, although they are attached to most of the Zeppelins, are seldom used in night raids.""I should like to have seen it, all the same," Helen confessed."You would have been disappointed," her informant assured her. "By-the-by," he added, a little awkwardly, "are you not expecting Lady Cranston back this evening?""I am expecting her every moment. The car has gone down to the station to meet her."Captain Griffiths appeared to receive the news with a certain undemonstrative satisfaction. He leaned back in his chair with the air of one who is content to wait."Have you heard, Miss Fairclough," his younger companion enquired, a little diffidently, "whether Lady Cranston had any luck in town?"