Telescope Hill trouble -- Over the fence -- Bouncy quill -- A hazing trick -- Counterattack -- The toppled tower -- The Palais Paris -- The old man's warning -- The cavern -- A terrifying loss -- No trespassing! -- Undercover work -- A straight-line clue -- Startling news -- A growing suspicion -- Deadly clicking -- A bold warning -- Searchlight -- A raft of trouble -- Loyal pals.