The hidden underground and new magic (Ice age x OCs)

After the events of The Meltdown. The Herd survives the flood and found a new home, Manny and Ellie are married and they're planning to have a child. Despite this, Manny is very determined and overprotective to make life perfect and doesn't want to have a same fate just like his previous family. On the other hand, Diego decided to leave the Herd because he fears that he's losing his predator side much of Eleanor's sadness while the group of humans celebrates Rose's 10th birthday which her powers evolves just like Eleanor's power.

Meanwhile, Sid begins to wish for a family of his own instead he finds a 3 abandoned eggs in the icy cave. Later, the 3 eggs hatches into a 3 baby Tyrannosaurus Rex, although Sid tries his best to raise the 3 baby T-rex, their rambunctious behavior cause to scare the children away. However, things got bad, A female Tyrannosaurus Rex kidnaps Sid along with her 3 T-Rex kids. The Herd must rescue Sid before it's too late. Soon later, they entered the icy cave which leads them into a jungle populated with Dinosaurs. Later, they met a fearless yet insane male weasel named Buck in the jungle. They decided to team up with Buck but the weasel told them about his story and the lost of his right eye from the Albino baryonyx named Rudy.

Together, they must rescue Sid from Rudy then only they find themselves met a new humans with new gifted powers and animals who are Buck's friends.