The Land Before Time XVIII: Journey Under the Great Valley

Littlefoot has hit the Time of Great Growing and has a rebellious streak. He has made new friends and started to shun his old ones. He begins to covert a legendary rock known as the Fire Rock, which is said to be under the Great Valley and bestow knowledge and wisdom to its finder. As he sets out for the Fire Rock, however, he starts to learn who his real friends are and aren't.