Jack, Peggy, Mike and Nora are off on another exciting adventure when they run away to Africa, with their friend Prince Paul, in a desperate search for their parents who are being held captive in the Secret Mountain . But where is the mountain? And who are the strange red-haired people who live there? The rescue mission seems destined to fail..Then, on top of everything, the children are taken captive. And one of them is to be sacrificed to the Sun-god.