The Hidden Harbor Mystery by Franklin W. Dixon

ankles.
    â€œReady!” he called.
    Frank loosened his foothold but held fast to the spindles as Joe gave a mighty swing, carrying both boys into the air. Joe, finding he could reach the next balcony, hooked his knees over its railing, let go his grip on Frank, and pulled himself up. But just as he stepped to safety, a fresh gust of wind whirled the white paper upward and away.
    The paper sailed farther and farther. Finally it disappeared around the corner of the house.
    Now, trying the french windows on his own balcony, Joe found them locked securely. The boys groaned and Frank said, “This would have been a swell time to follow the fellow in the raincoat.”
    â€œI’ll bet he locked us in,” Joe reasoned. “He left the secret door through the closet open and the light on in the study, to trap us.”
    Frank had another theory. “Maybe it wasn’t Rand whose steps we heard. Someone else could’ve set the trap. The professor might’ve been here the whole time and never realized what was going on.”
    Suddenly, between rushes of wind, a faint whistling came to the boys’ ears from the grounds.
    Who could that be? the Hardys wondered.
    Again the whistling came. Then a white-shirted figure crept cautiously out in front of the house.
    â€œChet!” called Frank with relief.
    â€œHere I am,” came the reply. “Got tired of waiting in that old passage. What are you two doing up there, anyhow?”
    â€œWe’re locked out,” Joe told him. “See if you can get into the house and free us.”
    The stout boy marched up to the front door, and tried it. “Locked,” he muttered. Almost automatically he stooped and looked under the mat. “Yes. Here we are—a key.”
    Inserting it in the lock, Chet opened the heavy door and vanished inside. In two minutes he freed Joe, then Frank. “That was easy,” he said. “Where do we go now?”
    â€œBack outside,” Frank answered. “We have a flying clue to bring down!”
    After bolting the room door, the three raced downstairs, locked the front door, replaced the key, and ran around the house. By now the dusk had deepened.
    â€œNo flashlights,” said Frank. “We’ll have a better chance to see the paper against a dark background.”
    Frank turned his gaze upward. “There it is!” he announced.
    High in the wisteria covering the wide chimney, fluttered the white square of paper.
    â€œOh-h,” moaned Chet. “Three of us standing on each other’s shoulders couldn’t reach that high.”
    â€œNo, but if the top man had a stick, he might,” Frank pointed out.
    While Chet and Frank kept watch on the unpredictable paper, Joe found a fallen branch.
    â€œYou’re elected anchor man, Chet,” Joe said, returning. Frank hauled himself up to stand on the stout boy’s shoulders. Then Joe hoisted himself up onto his brother’s. He clutched the wisteria vine for balance and began to fish upward with the stick.
    â€œCan’t ... reach it.” Joe grunted, extending to his utmost length.
    â€œYou’re stepping on my ear,” warned Frank.
    In desperation, Joe took aim and flung his branch upward. With a rustling of leaves, the paper came free. The human ladder collapsed, the Hardys breaking their fall by somersaulting. The trio dashed after the white square, which now sailed toward the back of the house.
    Here the wind was not so strong. The paper lost altitude, and Joe, rushing up with a cry of triumph, made a neat two-handed catch.
    While Chet held his flashlight, the Hardys examined their find. Two sheets of white paper were stapled together. The one on top appeared to be a carefully hand-drawn map.
    â€œIt’s the Rand property,” said Frank. “Here’s the house, with the pond and swamp behind. But what’s this encircled area?” Squinting closer, he read the small printed words which