It is first shown two big male Tyrannosaurus rex were fighting in a beach of Hell Creek, Montana in the Late Cretaceous period (66 M.y). The two males are called Jack Palance and Stumpy. Jack Palance eats the right arm of Stumpy and drives him away. Later is seen Stumpy and his mate Tinkerbelle with their two youngs that were chasing a young Pachycephalosaurus but they were then driven to Jack Palance territory and they are killed by him. When the parents discover the death of their youngs, in the next day they decide to hunt a Triceratops. The hunt was successful but Jack Palance appeared in the zone and planned to attack Stumpy. Jack Palance tries to eat is left arm, but Tinkerbelle helps and bites Jack Palance leg. With the Stumpy free he pushes his rival and falls into the horn of the Triceratops which perforates Jack Palance's neck. In that night Stumpy and Tinkerbelle mates.
Two years later, Tinkerbelle puts a cluch of eggs. She protects is nest from heavy rains and hungry Troodons. When the eggs were mostly hatching, Tinkerbelle ear some squicks in the nest, but when she checks for hatching babys she just find some satisfied mammals. Just one egg survived, and the female Tyrannosaurus rex puts the egg on it's mouth and shakes it amenably until the egg shell brake. Then hatched a new feathered Tyrannosaurus called Junior.
Eight years later, Junior was now a teenager. An Ankylosaurus was walking on the beach to eat some berries. While he was eating, a Pachycephalosaurus was hiding below the Ankylosaurus belly to escape from hungry Troodons. The Ankylosaurus accidentaly sits on one of the Troodons and the small herbivore escapes later notices that they were chasing him. When the Ankylosaurus got up, the pair of raptors ran away. Junior come to the beach and played with the Ankylosaurus but the herbivore attacks him with the tail, and the young predator escapes with an injury. Later, Junior chases the pair of Troodons into a cave, just in the time when the massive asteroid crashes on Earth.
Later, Junior gets out of the cave in the nuclear winter finding it's parents dead. Then, the young Tyrannosaurus rex was distracted by a mammal, but when was attacking he falls down a cliff and dies. The pair of Troodons have survived and persisted with more of their kind. The male was hatching his eggs, and the female came back to the out world to hunt something. There were a cockroach that escaped from the chasing Troodon but the dinosaur is then distracted by the dead Junior and eats some small pieces. When the female comes back to the nest he finds his mate frozen. Their eggs have been also the same destiny, except one. The female kept with the surviving egg and hatches it on the dead Junior's mouth. In the end it is found that Dinosaur Revolution continues with the modern birds.