This episode followed the life of a young female herbivorous Diplodocus. After hatching at the forest edge, she and her siblings retreat to the safety of the denser trees. As they grow, they face many dangers, including predation by Ornitholestes and Allosaurus, and a Stegosaurus, which kills one by accident while swinging its tail. Close to adulthood, the group of young Diplodocus are nearly all killed by a huge forest fire and fire storm that night, leaving three, then two survivors including the female. They are driven out onto the open plains, where they find a herd. The protagonist female mates, but not long afterwards is attacked by a bull Allosaurus. She is saved when another Diplodocus strikes the allosaur with its tail. In the end, her species will only get bigger.