Before disappearing into the jungle in southern Mexico, a couple of archaeologists managed to send their children a parcel containing an expedition diary and a gold coin from the Mayan era. Following this trail, the young naturalist Jake Ransom and his flighty sister Cady suddenly found themselves in an extraordinary world called Calypsos. Fragments of long-vanished civilizations were preserved there. People and dinosaurs get along with each other there. There, masters of alchemy, striving for absolute dominance, acquire armies of monsters...