Nick long had known him by name and sight, the only son of wealthy Henry Mantell, of Mantell & Goulard, the owners of the vast Sixth Avenue department store to which reference already has been made, and which then was by far the largest establishment of its kind in the country. He was Frank Mantell, of whom Helen Bailey had spoken to Nick in connection with the robbery committed by her recreant brother. “Come to the point, eh?” he replied, still smiling. “That is a very good suggestion, Mr. Carter, and I will act upon it. Mr. Goulard, the junior partner of our firm, was to have met here to discuss our business with you. Pending his arrival, however, I will do what you suggest and tell you why I am here.” “Very good. I am all ears,” Nick remarked, knocking the ashes from his cigar. “I am here, Mr. Carter, because of the tremendous leak in our business,” said Frank, more gravely. “I refer, of course, to the department store of Mantell & Goulard, of which I am one of the managers. My father, you know, is the senior partner.” “I am acquainted with your father,” Nick bowed. “When was this leak discovered?” “Six months ago, after our semiannual taking of stock. Our business showed a shrinkage of more than thirty thousand dollars. That of the past six months is even worse, running close to fifty thousand. In other words, Mr. Carter, the leakage the past year is close upon eighty thousand dollars.” “Much too large to be charged to the profit-and-loss account,” said Nick. “Are you unable to discover the cause?” “Quite the contrary, Mr. Carter,” said Mantell. “We know the cause.” “Namely?” “Robbery.” “Money?” “No. Merchandise.” “You don’t mean that eighty thousand dollars’ worth of merchandise has been taken from your store in the past year, and that you are unable to discover the thieves,” said Nick. “That is precisely what I mean,” Frank replied, a bit more forcibly. “As a matter of fact, Mr. Carter, we are up against a most extraordinary game of systematic and persistent robbery. Day after day, and frequently during the night, articles of material value disappear most mysteriously from all parts of the store. We don’t know where they go, nor how the thefts are committed. We have not the slightest clew to the identity of the robbers.” “What kinds of goods are chiefly missing?” “All kinds, but invariably articles of considerable value. Costly laces of every description, fine handkerchiefs, pocketbooks, and jewelry, full pieces of expensive silks and satins, fine lace draperies, and--but I could not begin to enumerate them. They disappear as if they had evaporated from our shelves, counters, and show cases.” “Can it be the work of professional shoplifters?” “Impossible; utterly impossible! It is much too extensive.” “How about your help?”