"Well," Plummer answered, a little doubtfully, "we're glad of outside help, of course, but I'm not sure, officially——"
"Of course you are always glad of outside help," Hewitt interrupted, "and in this case we may possibly find Brett more useful than you think. Consider now. He has seen a good deal of these cases—quite as much as you, in fact—but he is the only one of the three of us whom Mayes does not know by sight. Remember, Mayes saw us both in the affair of Mr. Jacob Mason, and he saw you again in the case of the Lever Key—escaped, in fact, because he instantly recognised you. I'll answer for Brett's discretion, and I'm sure he'll be glad to help, even if, for official reasons, you may not find it possible to admit him wholly into your counsels."
Of course I willingly assented, and the conditions understood, Plummer offered no further objection. Hewitt despatched his telegram, and in a very few minutes we were in a cab on the way to the Admiralty.
"This is the way of it," Plummer said. "You will remember that when we lost Mayes at the end of the Lever Key case, I was waiting for him in that city office, with an assistant, and that we only saw him for an instant in the lift. Well, that assistant was a very intelligent man of mine, named Corder—a fellow with a wonderful memory for a face. Now Corder is on another case just now, and we'd put him on, dressed like a loafer, to hang about Whitehall and the neighbourhood, watching for some one we want. Well, this morning there came an urgent message to the Yard from the Admiralty, to ask for a responsible official at once, and I was sent. As I came along I saw Corder lounging about, and of course I took no notice—it would not do for us people from the Yard to recognise each other too readily in the street. But Corder came up, and made pretence to ask me for a match to light his pipe; and under cover of that he told me that he had seen Mayes not an hour before, coming out of the Admiralty. At this, of course, I pricked up my ears. I didn't know what they wanted me for, but if there was mischief, and that fellow had been there, it was likely at least that he might have been in it. Corder was quite positive that it was the man, although he had only seen him for a moment in the lift. He hadn't seen him go into the Admiralty office, but he was passing as he came out, and noted the time exactly, so that he might report to me at the first opportunity. The time was 11.32, and Mayes jumped into a hansom and drove off. He walked right out into the middle of the road to stop the hansom—you know how wide the road is there—so that Corder couldn't hear his direction to the cabman, but he took the number as the cab went off. Corder ought to have collared him then and there, I think, but he was in a difficult position. It would have endangered the case he was on, which is very important; and besides, he didn't realise how much we wanted him for, having only been brought in as an assistant at the tail of our bond case. Still less did he guess—any more than myself—what I was going to hear at the Admiralty office."
"At any rate," interrupted Hewitt, "you've got the number of the cab?"
"Here it is," Plummer answered, "and I've already set a man to get hold of the cabman. You'd better note the number—92,873."
Hewitt duly noted the number, and advised me to do the same, in case I should chance to meet the cab during the afternoon; and as we neared our destination Plummer gave us the rest of the case in outline.
"In the office," he said, "I found them in a great state. A copy of the code, or cypher, in which confidential orders and other messages are sent to the fleet all over the world, and in which reports and messages are sent back, had disappeared during the morning. It was in charge of a Mr. Robert Telfer, a clerk of responsibility and undoubted integrity. He kept it in a small iron safe, which is let into the wall of his private room. It was safe when he arrived in the morning, and he immediately used it in order to code a telegram, and locked it in the safe again at 10.20. Two hours later, at 12.20, he went to the safe for it again, in order to de-code a message just received, and it was gone! And the lock of the safe is one that would take hours to pick, I should judge. There isn't a shade of a clue, so far as I can see, except this circumstance of Mayes being seen leaving by Corder—just between Telfer's two visits to the safe, you perceive. And of course there may be nothing in that, except for the character of the man. And that's all there is to go on, as far as I can see. I needn't tell you how important the thing is at a time like this, and how much would be paid for that secret code by a certain foreign Government. We have made hurried arrangements to have certain places watched, and as soon as I have taken you to the office I must rush off and make a few more arrangements still. But here we are."
Mr. Robert Telfer's room was at the side of a long and gloomy corridor on the upper floor, and the door was distinguished merely by a number and the word "Private" painted thereon. We found Mr. Telfer sitting alone, and plainly in a state of great nervous tension. He was a man of forty or thereabout, thin, alert, and using a single eye-glass. Plummer introduced us by name, and rapidly explained our business.
"I told you the name of the party I am after, Mr. Telfer," Plummer said, "and I went straight to Mr. Martin Hewitt, as being most likely to have information of him. Mr. Hewitt, whose name you know already, of course, is kind enough, seeing we're in a bad pinch, and pushed for time, to come in and give us all the help he can. Both he and his friend, Mr. Brett, know a good deal of the doings of the person we're after, and their assistance is likely to be of the very greatest value. Do you mind giving Mr. Hewitt any information he may ask? I must rush over to the Yard to put some other inquiries on foot, and to set an observation or two, but I'll be back presently."