What a wonderful, exciting adventure they have—Nora, Mike, Peggy and Jack—on their summer holidays. They go to Prince Paul's magnificent castle at Killimooin, high up in the mountains of Baronia. Little do they suspect that these mountains hold a dangerous band of robbers who are intent on capturing them and Prince Paul!
Prince Paul, Jack, Peggy, Nora and Mike have come to Africa on what seems an impossible search. Yet they mustn't give it up because Captain and Mrs Arnold have been kidnapped and taken to the Secret Mountain. But where is the mountain? And who are the strange red-haired people who live there? Their rescue expedition seems destined to fail, until they meet young Mafumu...
What excitement for Mike, Jack, Nora and Peggy when they discover the secret caves and passages of Spiggy Holes! And when they find out that a kidnapped prince is being held captive in the old house above the caves, they're in the grips of another adventure! The boys attempt to free the prince in the dead of the night—but Mike is caught and he, too, is taken prisoner...
Four runaways, Mike, Peggy, Nora and Jack, find a secret hiding place—a deserted island on a lovely lake. They build a willow-tree house, make their beds of heather and bracken, and grow their own vegetables. And Jack even manages to bring his cow, Daisy, and some hens to the island for fresh milk and eggs every day! But one day invaders come to the secret island...
"It's old walls could tell tales of violence and mystery"—that's how Moon Castle was described. So naturally, Jack, Peggy, Mike and Nora are thrilled when Prince Paul's family rent it for the holidays! But what weird things happen—musical instruments play by themselves, books leap off the shelves, and pins and needles attack the children! What secret does the castle hide?
