On the night of the Black Tom explosion, early in August, Dick didn't show up at the Library at the usual hour, and, while this didn't worry Mary, because it had happened several times before, she began to be annoyed when three nights passed the same way. Of course, she had no way of knowing that the Service had received a tip from a stool pigeon on the pay roll of the New York police force that "a bunch of Germans were planning a big explosion of some kind" just a few hours before the earth rocked with the force of the blow-up in Jersey. Every government operative in the city had been informed of the rumor, but few of them had taken it seriously and not one had any reason to expect that the plot would culminate so close to New York. But the echo of the first blast had hardly died away before there were a dozen agents on the spot, weaving a network around the entire district. All they got for their pains, however, was a few suspects who very evidently didn't know a thing. So it was a very tired and disgusted Dick who entered the Library four nights later and almost shambled up to Mary's desk. "I'll be off duty in half an hour," she told him. "From the way you look, you need a little comforting." "I do that," he admitted. "Don't make me wait any longer than you have to," and he amused himself by glancing over the late seekers after knowledge. When they had finally seated themselves in a cozy corner of a little restaurant in the upper Forties, Dick threw caution to the winds and told Mary all about his troubles. "I haven't the least business to do it," he confessed, "and if the chief found it out I'd be bounced so fast that it would make my head swim. But, in the first place, I want you to marry me, and I know you wouldn't think of doing that unless you knew something more about me." There was just the flicker of a smile around Mary's mouth as she said, almost perfunctorily, "No, of course not!" But her intuition told her that this wasn't the time to joke, and, before Walters could go on, she added, "I know you well enough, Dick, not to worry about that end of it." So Walters told her everything from the beginning--and it didn't take more than five minutes at that. Outside of the fact that his people lived in Des Moines, that he had been in the Secret Service for eight years, and that he hadn't been able to do a thing toward the apprehension of a certain German spy that the government was extremely anxious to locate, there was pitifully little to tell. "The whole thing," he concluded, "came to a head the other night--the night I didn't show up. We knew that something was going to break, somewhere, but we couldn't discover where until it was too late to prevent the explosion across the river. Now that they've gotten away with that, they'll probably lay their lines for something even bigger." "Well, now that I've told you, what d'you think?" "You mean you'd like to marry me?" Mary asked with a smile.