Once or twice, on bright days, I made a short flight just to keep fit. Otherwise I generally remained at home in my rooms pondering, or else out trying to follow some imaginary clue to which my theory led me.

Lionel Eastwell always expressed himself full of sympathy. Many times we met at the club and elsewhere, and he always expressed his belief that Roseye was somewhere with friends. Indeed, he seemed full of optimism.

“My firm opinion is that Miss Lethmere has met with an accident, and is in some hospital or other—some cottage hospital perhaps. Maybe she has lost her memory as result of her unfortunate mishap,” he suggested one day. “There are lots of such cases recorded in the papers.”

Truth to tell, my suspicion of Lionel Eastwell had daily increased. First, he had always appeared far too inquisitive regarding our experimental work. Secondly, he had been ever polite and affable towards Roseye with a view, it seemed, of preserving an extremely close friendship. Why, I wondered? I knew that she had liked him for his courtesy and pleasant demeanour ever since they had first met. And the point that they had first met in Germany I had never forgotten. It had increased my suspicion—and pointedly so.

The most puzzling fact concerning him, however, was that I had discovered during my eager and constant investigations, from one of the boys at Hendon—Dick Ferguson, who was flying a new REP “Parasol,” that on the very evening of the day that I had called at Albemarle Street to find him ill in bed, he had met him in Hatchett’s in Piccadilly, and had actually dined with him there in the grill-room.

When I had sat at Eastwell’s bedside, three hours before, he had then declared himself unable to move without pain, and had told me that the doctor had strictly forbidden him to get up. Yet, on that very same night, he had dined down below in the cheerful grill-room and, according to Dick, was as merry as ever.

These were facts which certainly required explanation.

Why had he not gone along to the Piccadilly Hotel, or to the Club, as was his habit? Was it because, fearing to be seen, he had chosen the smaller and quieter resort?

Most probably he feared to meet either Teddy or myself at the Piccadilly, for we both frequently went there as a change from the Automobile Club. We flying-men are a small circle, and we have our own particular haunts—just as every other profession has.

Three times I had questioned Dick Ferguson regarding Lionel’s presence at that small, but popular restaurant on that particular night. At first I believed that he had probably mistaken the date—which was so easy. But he had fixed it absolutely by telling me that it was the night when the Admiralty had admitted that Zeppelins had again been over Essex and Norfolk and been driven back by our anti-aircraft guns.