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.
"I can do nothing just yet, except to receive reports from you," replied Gerald. "You can visit Boyne's house and let me know from time to time what is in progress there."
"But the prisoner upstairs?" she asked. "How can I know more?"
"By watching," was his reply. "Do you know, Marigold, I've been thinking--thinking deeply over the affair. We are both agreed that we intend to fathom the secret of this man. Well, now could you not one evening, when you visit your aunt, be taken suddenly very unwell, and then remain there in the house and watch?"
"Really, Gerald, that's a splendid idea!" exclaimed the girl. "Yet it seems an imposition upon Mr. Boyne."