The Hidden Harbor Mystery by Franklin W. Dixon

she’s staying here, but she’s gone for the day to the amusement park on the boardwalk.”
    Now the trail was getting hot! When they reached the amusement section, Bart parked his car, and the four walked onto the crowded boardwalk.
    It was just after lunchtime. Crowds of vacationers were just leaving a cluster of tables shaded by great beach umbrellas near a boardwalk restaurant.
    â€œThere!” cried Bart, pointing.
    A middle-aged woman with gray hair was seated at one of the tables. She was sipping an ice-cream soda. As Worth called to her, she looked up at him. Instantly she jumped up, grasped a black purse, and scuttled away.
    â€œJenny! Wait!” called the editor, as he and the boys dashed after her.
    With surprising speed, Jenny Shringle dodged in and out of the throng. Frank gained on her.
    â€œMiss Shringle!” he cried out.
    She glanced back with a panicky look but did not slow down.
    Suddenly she darted off the walk and halted at one of the amusement ticket windows. The next minute the four friends, running toward her, saw her disappear into a brightly painted “fun house” billed as Bluebeard’s Palace.
    At one side of the high, bizarre building, a well-greased wooden slide shot the screaming customers down to the boardwalk.
    Chet folded his arms. “Well,” he said, “all we do is wait here till Jenny Shringle comes out. She can’t stay in there forever.”
    Bart shook his head. “This fun house is too rough for a woman of Jenny’s age.”
    â€œWe’d better go in,” Frank agreed, “before she gets hurt. Bart, you wait here.”
    He quickly purchased admission tickets, and the three boys entered the fun house. Frank led the way through a dark, narrow tunnel. Chet followed, then Joe.
    As fast as possible, they stumbled forward. Weird screams startled them. Hanging cobwebs brushed their faces. Slithery, snakelike forms writhed underfoot. Finally reaching a level place, they walked ahead rapidly—only to find themselves on a treadmill carrying them backward!
    At last, Frank, stepping off the treadmill after the others, entered a dimly lighted chamber with distortion mirrors around the walls.
    Suddenly he stopped short. Confronting him was a wide-shouldered, giant figure with a very narrow waist. Frank burst out laughing. It was his own image, greatly exaggerated! Then, reflected behind him loomed another figure of gorilla-like proportions, with a familiar flattened face.
    â€œI warned you!” a hoarse voice rasped.
    As the huge arms grabbed for him, Frank ducked nimbly into the next room. In the weird half-light the boy saw that the floor tilted sideways, and the walls were tipped crazily. Frank found that he was forced to run downhill without being able to stop himself.
    In another instant he bowled, helpless, into Chet and Joe, who had just picked themselves up at the far wall. The next second, the heavy bulk of the flat-faced man hurtled into their midst. All four went down on the floor in a heap.
    Frank, who had been struck hard in the pit of the stomach, gasped for breath. As the four rolled about in a violent struggle, he caught the gleam of a knife in the big man’s hand!

CHAPTER VIII
    Campfire Eavesdropper
    â€œLOOK out!” Frank yelled. “He has a knife!”
    The boy threw himself on the man’s brawny forearm, seized his wrist, and clung to it grimly.
    As their antagonist struggled for a foothold, Joe dived under the blade for an ankle-high tackle. The man smacked heavily into the inclined floor, where Chet pounced on his chest.
    All this time Frank had clung to the man’s arm. Now he gave the thick wrist a sudden twisting wrench. The man gave a roar of pain. His big fist opened, and the knife slid harmlessly away over the tilted floor.
    â€œThis fun house isn’t much fun any more!” Joe exclaimed.
    Savagely the big man kicked and lashed out. The boys gave hard, chopping blows in