"Don't make any noise," he cautioned. "Mrs. Blarcum is in her room, but she has good hearing in spite of her age, and I think she is somehow mixed up with the mystery. Now we'll go to the top floor," and he took up a big poker, which was on a chair in the side hall. "What's that for?" asked Bert. "We may have to smash down a door or two, or pry them open. This is the only thing I could find. Now come on." They cautiously ascended the stairs. When they reached the top floor, they found a stout door barring their progress. Mort Decker tried to insert the point of the poker in the lock, to force it, but, finding he could not do this, he raised the heavy iron, to break the panels. At the first blow there sounded from the other side of the portal a cry: "Help! Help! Let me out!" "Who are you? Why arc you in there?" asked Mort, pausing in his attack on the door. Before he could distinguish the answer, if one was made, there sounded from behind the two rescuers, a woman's scream, and they turned to see Mrs. Blarcum rushing at them. "Come away from there!" she cried. "Come away! Mr. Muchmore doesn't allow any one there!" "I don't care what he allows!" retorted Mort. "We're going to get at the bottom of this mystery!" Once more he rained a shower of blows on the door. "Get away from there!" cried the old woman, rushing up, and grabbing the stenographer by the arm. "Help! Help!" she added. "Mr. Muchmore, he is breaking down the door to the secret corridor!" Suddenly there sounded from below the rush of feet. Then came a startled cry. "I'm coming!" some one shouted. "Muchmore! It's Muchmore!" exclaimed Mort, pausing. "If he finds us here--" "Let's stick it out!" urged Bert bravely. "We'll find out what this means!" An instant later, Muchmore, his face distorted with anger, rushed upon them. CHAPTER XXV THE MYSTERY SOLVED--CONCLUSION "Get away from that door!" yelled the enraged man. "What right have you to be prying into my affairs? I hired you to do copying work for me, not to roam about this house." "Well, I'm done copying those illegal deeds for you!" retorted Mort. "And, what's more, we're going to find out whom you have a prisoner in there!" "A prisoner? You are joking. There is no one in there." "Yes, there is. He wrote an appeal for help on the typewriter and tossed the paper from the window. Hark, you can hear him calling for help!" There was a moment's silence, but no cry came from behind the door, one panel of which was shattered. "You see," sneered Muchmore. "I guess you'll wish you hadn't begun this work, my friend, before I'm through with you. You'll be in jail ere you are many hours older. As for you," went on the man, turning to Bert, "I warned you, once before, not to trespass on my property. I shall also make a complaint against you. Now, clear out, both of you!" "Suppose I refuse to go?" asked Mort coolly.