Join Julian, Dick, Anne, George, and Timmy the dog as they embark on a thrilling horse-drawn caravan holiday. Their idyllic adventure through the sunny Merran Hills takes a suspenseful turn when they encounter a traveling circus, make a loyal new friend in Nobby, and discover a massive, hidden underground cavern system used by ruthless criminals. This classic Enid Blyton tale perfectly blends the cozy freedom of the open road with a high-stakes mystery of courage, loyalty, and justice.