The jolly dinosaurs from the Great Valley return for another song-filled adventure. When heavy rain creates a mysterious 'new water', Littlefoot (Thomas Dekker) sets off to explore the Great Valley. He quickly becomes friends with Mo (Rob Paulsen), a prank-playing dolphin-like creature who can't find his way back to the Big Water. Littlefoot and his prehistoric pals come to the rescue, evade a scary sharptooth - and prove the value of courage, friendship and diversity. The film features the song 'No One Has to be Alone' by Donny Osmond.