The First Battle of Platus was a battle between the plateosaurus and an invasion party of T. rexes over the planet of Platus. The plateosaurus had earlier left the planet in an attempted return to Earth, but were decimated in a cosmic storm, which wiped out most of their fleet. The survivors came home to find that a group of T. rexes had taken advantage of their absence to take over the planet. The plateosaurus fought to reclaim their home, but a combination of their inexperience and a disadvantage in numbers led to a serious defeat. The horrors of the First Battle of Platus caused the remaning plateosaurus to become strict pacifists.