Ice Age Dawn of the Dinosaurs is the continuation of the Ice Age series. The movie begins with Ellie and Manny expecting their first child together. Since his previous family were killed in the early years, he is overprotective of mother and child. She complains about him attempting to "baby proof nature" which is a sore spot for her. Sid is jealous of Manny and Ellie having a baby and runs across three eggs which he quickly adopts as his own. Manny confronts him about the eggs and tells him that he is never going to be a good parent which causes Sid to leave the herd that he so diligently worked to create. The three eggs soon hatch into baby dinosaurs and their mother comes to take them away. Sid refuses to give them to her so she takes her young and Sid with her into the Earth.
Manny sees Sid get taken and rushes to help Diego retrieve him. Ellie insists on going along while Manny attempts to convince her that it would be too dangerous. The group runs across Buck which is a weasel that has been left on his own a little too long. He agrees to guide them to the Momma dinosaur to rescue Sid as long as they follow his ever changing rules. As the herd gets close to Sid, Ellie goes into labor and a pack of dinosaurs try to attack her. There is a rock slide that separates her from the rest of the group. Manny and Diego stay while the others help Buck rescue Sid. As soon as Manny and Diego finish fending the dinosaurs from attacking Ellie, she gives birth. She and Manny agree to name their little girl Peaches and the group heads back to the surface world. Buck remains behind to fight the dinosaur, Rudy. He seals the inner world from the surface as soon as the group crosses the threshold.