Free (#25) The Ghost of Blackwood Hall by Carolyn Keene

and pressing the keys down firmly. “I certainly didn’t dream I heard music coming from this organ! There must be a trick to it somewhere!”
    Now deeply interested, Nancy began to examine the instrument inch by inch with her flashlight. There was a small space along the side wall, large enough for a person to squeeze behind. Peering in curiously, she was amazed to see a duplicate set of ivory keys at the rear of the organ!
    “Why, the front of the organ is only a sham!”
    Eager to investigate, Nancy pushed through the opening. There she found a low door in the wall of the room. “So this is how the ghost vanished so quickly!” she told herself.
    Nancy tried the door, which was unlocked. Flashing her light, she saw that a flight of stairs led downward. Cautiously she began to descend. Only after proceeding a short distance along a damp, musty corridor did she regret that she had not summoned her father and Ned.
    “They may wonder what’s become of me,” she thought. “I mustn’t be gone long.”
    Intending to make a speedy inspection, Nancy quickened her steps along the corridor.
    “This must be the secret tunnel the book mentioned!” she said to herself.
    Soon Nancy came to a heavy walnut door, blocking the passageway. Her light revealed an iron bolt. As she slid it back and pushed the door open, she drew in her breath in sharp surprise. A strange green light on the floor of the room beyond illuminated the back of a ghostly figure standing just ahead of her!
    Simultaneously, the flashlight was struck from her hand. It crashed on the floor and went out. The green light also faded away.
    Fearful of a trap in the inky darkness, Nancy backed quickly into the corridor, slamming the heavy door and bolting it. Her heart pounding, she felt her way along the tunnel wall. Finally she stumbi-d up the stairway and through the exit behind the organ.
    “Whew, that was a narrow escape!” she thought breathlessly. “I must find Dad and Ned.”
    Nancy hurried from room to room, upstairs and down, but did not see either of them. She was tempted to call out their names but then thought better of it. Very much concerned, Nancy decided that they must have left the house to investigate the grounds.
    As she circled the mansion, the young detective tried to figure out under which room the secret tunnel had been built, and where it led. She noted that there was no outside exit from the cellar as most old houses had. Remembering the length of the musty underground corridor, she could very well believe that the exit was some distance from Blackwood Hall—perhaps in the woods.
    When ten minutes or more had elapsed and neither Mr. Drew nor Ned had appeared, a harrowing thought began to disturb Nancy. Maybe the two of them were prisoners in the tunnel room! They might have found the outside entrance to the tunnel and been captured!
    Frightened by this possibility, Nancy wondered what to do. Her first instinct was to go to the police. Then she realized that she could not drive the car to get help, because her father had the keys in his pocket. She finally decided that she would have to go back to the underground room at the end of the corridor alone and find out if her father and Ned were being held captive.
    Forgetting any thought of safety for herself, she entered the house again. She ran to the organ room and squeezed through the opening to the secret door. There she closed her eyes for several seconds until they became accustomed to the darkness, then carefully she picked her way down the steps and along the passageway.
    Reaching the heavy walnut door, she stooped down to look under the bottom for a light beyond. There was nothing but blackness.
    Trying not to make any noise, Nancy slid the iron bolt and cautiously opened the door a crack. The place was dark. When nothing happened, Nancy decided to take a chance, and called out:
    “Dad! Ned!”
    There was no answer. Yet she thought possibly the two men might be lying gagged or