As Littlefoot and his friends search for the stone of cold fire, they encounter a new dinosaur species, the mysterious "rainbow faces," who seem to be guarding the stone. The rainbow faces communicate with the young dinosaurs through telepathy and reveal that the stone has the power to grant wishes, but also has the potential to cause great destruction if misused.
Meanwhile, Littlefoot's uncle Pterano leads a group of villains on his own search for the stone, convinced that it will give him ultimate power. He convinces Littlefoot's own father, who has been absent for most of his life, to join him in the search, despite Littlefoot's protests.
As Littlefoot and his friends race to find the stone and prevent it from falling into the wrong hands, they must also grapple with their own desires and the consequences of their actions. In the end, they are forced to make a difficult decision to protect their loved ones and the world around them.