A young brontosaurus and his friends go into the mysterious beyond and find themselves in big trouble when they find an egg that turns out to be a Sharptooth; when a meteor cuts off the water supply in the valley, Littlefoot, Cera, Ducky and the other baby dinosaurs seek a new source; when Littlefoot's grandpa gets sick, he and his friends set out through the once-dry land of mists to retrieve the special night flower which will save him.