When Jamie and Tom get separated in the prehistoric jungle they each come across an enormous Permian beast . . . an estemmenosuchus and a moschops. Although shocked at first, they both realize that these are gentle plant-eaters and they're not in any danger. But as each of the giants spots the other one the boys realize that they may be harmless when they're left alone, but when another creature is on their territory, they don't like it very much . . . in fact, it makes them really angry! As the brutes battle it out, Jamie, Tom and Wanna have to try and come up with a way to stop the fight, before one of them gets hurt.