When Frank and Joe Hardy investigate a series of strange events near a rugged shoreline, they uncover a mystery that leads them into hidden caves, underground passages, and a dangerous criminal scheme. What begins as curiosity quickly turns into a race against time as the brothers realize that the caves conceal more than secrets - they hide a crime in progress. Trapped in darkness, threatened by collapsing tunnels, and pursued by ruthless enemies, the Hardy Boys must rely on courage, ingenuity, and teamwork to survive and bring the criminals to justice. Every step deeper into the caves brings new danger and higher stakes. The Secret of the Caves is a classic Hardy Boys adventure packed with suspense, physical danger, and fast-moving action. First published in 1929, the novel captures the series at its most thrilling, blending mystery, exploration, and youthful heroism. This Impact Books edition restores a high-energy adventure for readers who enjoy cliffhangers, hidden passages, and nonstop momentum.