Free Collision Course by Franklin W. Dixon Page A

can think up the plan next time."
    They worked their way down to a rather large ledge with a single scraggly tree that grew up against the cliff. Frank lashed the rope to the tree trunk to support Joe's weight while Joe put on the scuba gear. He double-checked the pressure in the tank, ran his hand over the air hose, and tested the regulator by breathing through it to make sure he was getting air from the tank.
    "Okay, I'm ready," Joe announced when he was sure everything was in working order.
    Frank tied the other end of the rope around Joe's chest, under his armpits. Then Frank took a firm stance with his legs wide apart and his knees slightly bent. Standing with his back to the tree, he wound the rope once around each of his arms and gripped the line tightly.
    "I'll do most of the work," he explained. "I'll let out the rope slowly. The tree will be a backup to hold you. You just keep yourself away from the cliff wall."
    Joe gave a tug on the line and then leaned backward over the edge. "Everybody into the pool!" he yelled, and pushed off with both feet.
    It worked perfectly. Joe relaxed a little as he inched downward. When he was close to the water line, he gave a firm shove with both feet, pushing himself out to clear a jumble of rocks at the bottom of the cliff. But suddenly the line went slack, and he splashed into the cold Atlantic, gasping and spluttering for air.
    The force of the fall had ripped the regulator from his mouth. A few swift kicks brought him back to the surface. "Nice going, ace!" he shouted up at his brother.
    There was no response. From this angle, Joe couldn't see the tree, the ledge, or Frank. He ducked underwater for a moment to wriggle out of the rope.
    Joe popped back up again and yanked off his face mask. He looked up again. He thought he caught a glimmer of movement, but he couldn't be sure. He was just about to shout again when he saw something hurtling over the side of the ledge.
    It was Frank — his arms and legs flailing — plummeting toward the rocks!

Chapter 11
    Frank hit the water hard, barely missing the rocks jutting out from the foot of the cliff. Stunned by the impact, he sank deeper and deeper beneath the waves into an engulfing darkness.
    At last, the cold, salty wetness woke him. At first he didn't know where he was or how he got there. I was standing on the edge of the cliff, he recalled. Then I was in the air, and now I'm underwater—with my hands tied behind my back!
    He thrashed around and discovered that his hands weren't really tied. He was just tangled up in the climbing rope. Frank unwound the rope and let it drift away from him. Then he kicked his way upward. His head broke the surface, and he greedily gulped in fresh air.
    Frank started to tread water and looked around to get his bearings. Suddenly someone else came out of the water right in front of him.
    "Take it easy! It's only me," Joe exclaimed pushing the diving mask up over his forehead. "Are you okay? That looked like a vicious fall.
    "Yeah," Frank said, wiping the hair out of his eyes. "If this were the Olympics, it would have been a perfect 0.0 dive."
    "What happened?" Joe asked. "Did the rope break?"
    "It had to have been cut back by the tree," Frank stated flatly.
    "What?"
    "I did a nosedive into the dirt on the ledge,' Frank said. "I thought the tree must have snapped or something."
    "So what changed your mind?"
    "Well, there I was, starting to get back up feeling pretty proud of myself for keeping hold of the rope—when somebody sneaked up behind me and gave me a nice, hard shove over the edge.
    "Well, whoever it was is gone now," Joe remarked, squinting up the face of the cliff.
    "I think we can get back up by climbing that rockfall," Frank said, pointing to a spot where the cliff had collapsed and a jumble of boulders sloped into the ocean. "I'll swim over and check it out."
    He started swimming but looked back over his shoulder. "You might as well dive down to the bottom and see if you can find