When adventurer Bowen Tyler was taken captive aboard an enemy submarine, he never dreamed that his voyage would end in the land that time forgot. It is a land called Caspak, a land of myth and fable: located somewhere on a mountainous island in the South Pacific, populated with winged, humanlike creatures, dinosaurs, ferocious beasts of prey, Neanderthals, "wild ape-men," and monstrous reptiles who all terrorize one another -- and Bowen Tyler, and the submarine''s mixed crew of World War I-era adventurers. Stranded on the beach, they fight their way across the island, through dinosaurs and Bronze Age warriors, saber-toothed tigers and cunning beast-men. They dine on Plesiosaurus steaks and face incredible dangers, meet and fall in love with a jungle princess -- and unravel the incredible secret of Caspak. . . .