Frank Harper was walking aimlessly up Fleet Street. His expression, as he turned into a tobacconist’s shop, was decidedly more clouded than that of a happily engaged young man should ordinarily be. He told himself, as he bought his cigarettes, that he was smoking a great deal too much. It was not the first time within the last few days that he had made the same reflection, and it had always ended in his going out somewhere and buying another packet. For whatever the voice of common sense might say, in the long run it was always his overstrained nerves that had the last word and drove him to seek relief. Even then, he knew, no relief could be anything but temporary, so long as the essential cause of the trouble remained unresolved. It lay in his pocket now, that cause, as it had lain for two days past—a letter from the girl he loved, asking, and asking insistently, the one question which he could not answer. And this morning another had been added to it, reproaching him for his failure to reply. Another would come soon, he knew—perhaps it would be a little more bitter than the last. And he, who had so lately been lifted to the summit of happiness, now saw himself travelling down a long slope leading to an inevitable quarrel—an estrangement, even. “If you won’t tell me, I can’t marry you!” Would it come to that? He shrugged his shoulders as he lit his cigarette. Well, if it came to that, it came to that! Meanwhile, there was nothing to do about it—except to smoke incessantly, and hope fervently that it wouldn’t. If a girl can’t trust a man, he thought bitterly—but what if a man can’t trust himself?

As he walked out of the shop he jostled a burly figure on the pavement. He murmured a perfunctory “Sorry!” and walked on. The man he had touched turned at the sound of his voice and walked quickly after him.

“Mr. Harper, isn’t it?” he said.

Harper looked round. For a moment or two he gazed blankly at the large man with the smart umbrella who had accosted him. Then a look of recognition came into his face.

“Ah, yes, of course. Inspector Mallett,” he murmured in his somewhat irritatingly superior manner.

Mallett’s eyes gazed keenly into the young man’s. For a fraction of a second there was a trace of disappointment in his expression, as though he failed to find what he had sought there. Then a smile illuminated his broad features.

“This is a bit of luck,” he exclaimed genially. “You’re just the fellow I wanted to see.”

“You know my address, I think, if you wish to ask me anything,” returned the other coolly.