The Land Before Time X: The Great Longneck Migration is the tenth film in the Land Before Time series.
Littlefoot has nightmares which involve the sun, or "Great Circle". He mentions it to his grandparents, who share the experience. Grandpa has a feeling that he wants to "go somewhere", and they leave the next day with no help but sense to tell them where they were going. Out of curiosity, the others follow him, starting after them the following night. But there's disaster after disaster as waking them up isn't easy for Cera.
New characters are introduced through the movie: "Sue", a Supersaurus, who is driven on by the same sense as Grandpa, joins Littlefoot; and Cera and the others sleep in a sleeping Daspletosaurus, and they met "Pat" who is an elderly Apatosaurus. Sue is always haunted by a want to meet someone taller than her, as she towers above everyone else. Pat is slow-moving, but does arrive at the crater in time for the event. He injures his foot due to volcano activity....