"I could have given you all the instructions that were necessary in the telegram I sent to your mother, but I thought it best that you come to Chicago first and have a little rest before resuming your journey. This would also give me a chance to tell you more about the mission I have decided to send you on. The truth of the matter is, I have been hurt, and am now laid up in a miner's cabin and have been unable to continue my investigations in the case I have in hand. For this reason I am calling on you to help me, for I think I can trust to your abilities by now by reason of the assistance you have given me in other cases. I did not want to worry your mother needlessly, which is the reason I did not mention my injury. It is not serious but it will be some time before I am able to be on my feet again, and, in the meanwhile, time is precious.
"In my investigations here I have discovered a secret concerning some stolen gold. It is this matter that I wish you to investigate for me. To do so it will be necessary for you to come to Lucky Bottom, Montana, at once. Have a good night's rest at the hotel and then come on here. I am under the care of a miner by the name of Hank Shale, and when you reach Lucky Bottom any one will be able to tell you where to find his place. I shall be expecting you, so do not fail me. I hope you have a pleasant trip. Do not worry about me, as I am in good hands and progressing favorably.
"Your dad,
"Fenton Hardy."
Frank put down the letter, with a low whistle.
"So that's the reason he called for us!" he said. "Dad's been hurt."
"He says it isn't very serious."
"It's serious enough when it means he's not able to be on his feet. Perhaps we ought to start out to him right away."
"Not much use of that," objected Joe. "We wouldn't gain much time and we'd be so tired when we got there that we wouldn't be of much use to him for a day or so. I think we'd better rest here to-night, as he suggests, and go on to-morrow."
Frank considered his brother's advice sound, and, after enjoying a good dinner, the boys went out and wandered about the busy streets for almost an hour, enjoying the sights of the Windy City. But it was a cold, bitter evening, and they soon sought the warmth and comfort of their hotel again, going to bed early, because they were tired after their long hours on the train.
They were told by the information clerk that their train would leave at eleven o'clock the following morning. This gave them plenty of time for a good sleep, a bath and a leisurely breakfast. When all their preparations for the continuation of the journey had been made they presented themselves at the desk in the lobby to check out. Frank paid the bill, and the boys were just about to move away from the desk when a neat, elderly man somewhat below medium height, came up to him.