When poachers kidnap Jackie Legs from the Australian Outback, his friends leap into action! Their attempts to save him route them back to the U.S. into the glitz and glamour of Las Vegas.
A huge meteorite has plunged into the Great Valley, cutting off the water supply and causing tension among the once-peaceful dinosaurs. While the adults argue and turn against one another, Littlefoot and his friends venture out to find a new source of water, only to be constantly bullied by a trio of older dinosaurs. The journey becomes a fight for survival when the group is cornered by a pack of Velociraptors and trapped by a sudden wildfire.
Littlefoot learns a series of important lessons following an incident that nearly costs his grandmother her life. Soon afterwards, three dinosaurs arrive claiming they have lost their way.
Legends claim that Saurus Rock keeps bad luck out of the Great Valley. Is it really true? Could the mysterious Longneck named Doc be the famous Lone Dinosaur, who can defeat a Sharptooth with his lasso-like tail To find out, Littlefoot and company must cross the great Valley and face a dangerous Sharptooth themselves!
When the dinosaur families get trapped in a valley by an ice storm, one family of "spike tail" dinosaurs volunteers to leave since they consume more food than the others. Meanwhile, the young dinos and a new adult dinosaur named Mr. Thicknose, head out to bring back their friend Spike, who has left his friends to be with members of his own species.
Littlefoot befriends with a mysterious, fun-loving dolphin-like creature named Mo, who is trapped in "new water" caused by heavy rain. The gang then goes on an adventure to the "big water" to bring Mo home.
When laidback Greg finds himself at odds with his dad's outsized expectations, pressure builds to turn his act around. After a series of hilarious near disasters, Greg's dad presents him with an ultimatum that just might challenge his wimpy ways for good.