Yet Durrant, with great pertinacity, waited there through the whole night until, at half-past six, the hall-porter threw open the outer door, and milkmen, the postman, and newspaper boys began to arrive in quick succession. Without bite or sup Gerald waited there till half-past ten, when, full of chagrin at being thus foiled, he was compelled to hurry to his office, getting a wash and a shave on the way. At lunch he met Marigold as usual, and told her of his failure, whereupon she said: "I have the afternoon off. I’ll go at once and see my aunt, and ascertain when he got back." This she did, and when that evening Durrant arrived home at Ealing he found a wire awaiting him which told him that when Boyne’s housekeeper took him up his early tea as usual, her master had been in bed! Durrant held his breath. The mystery-man had some means of exit from Upper Brook Street—a back way, without a doubt. But what was the motive of it all? Why should he pose as penurious in Hammersmith, and wear evening clothes in Mayfair? That night Durrant went again to Upper Brook Street, and, exploring the rear of the building, found that there was a servants’ entrance to the flats which led into a mews, and through a back street. By that Bernard Boyne had, no doubt, walked out while Durrant had been keeping his night vigil. This fact further impressed both Marigold and her lover that Boyne was not what he represented himself to be. Durrant set out to probe the mystery, and by dint of ingenious application to the affair, he became on friendly terms with the hall-porter. Truth to tell, Durrant had represented himself to be a demobilised officer who had been in love with a lady who had rented one of the flats. He had discovered her name from the house-agent, and knew that she had married during the war. From the hall-porter he learned that the man who had passed in was an occasional visitor, but to whom he did not know. He would try and ascertain. The lips of all hall-porters of flats are readily unlocked when their hands are "crossed with silver." And why not? In our post-war civilisation little is effected without a _quid pro quo_. Even the British Cabinet Minister looks for reward; alas! that it should be so. Patriotism in all the Allied Countries seems synonymous with personal ruin, and those who have realised the fact are the profiteers upon gallant men’s lives. Gerald’s discovery at the back of Upper Brook Street brought the pair to a dead end as far as their investigations went. They met as usual at lunch and discussed the situation. What could be done? "All I can see, Marigold, is for you to continue your visits constantly to Bridge Place and learn all you can from your aunt," Durrant said. "There is evidently something extraordinary in progress. But what it is we cannot possibly tell without more thorough investigation." "But what can we do further?" asked the girl.