The movie starts off with Littlefoot and his grandparents sharing a bedtime story about a group of longnecks who migrated to a faraway land with abundant food and water. Littlefoot becomes curious about this land and asks his grandparents if his father, who left before he was born, went on this journey too.
The next day, while playing with his friends Cera, Ducky, Petrie, and Spike, Littlefoot spots a lone longneck in the distance. Excited by the possibility of meeting his father, Littlefoot and his friends follow the longneck, who turns out to be his father, Bron.
Bron tells Littlefoot that he has come back to the Great Valley to take him on the journey to the new land, which he calls the "Great Beyond." Littlefoot is torn between going with his father and staying in the Great Valley with his friends.
The Great Valley herds decide to join the migration, and the group sets off on their journey. Along the way, they face several obstacles, including a herd of stampeding buffalos and a fierce sandstorm.
Bron and Littlefoot bond during their journey, and Littlefoot finally learns the reason why his father had to leave before he was born. They also meet other longnecks who have joined the migration, including a young female named Ali, who becomes friends with Littlefoot.
As they reach the Great Beyond, Littlefoot and Bron part ways, and Littlefoot decides to stay in the Great Valley with his friends. However, he promises to meet his father again and explore the Great Beyond together someday.
The Land Before Time X: The Great Longneck Migration is a heartwarming tale about family, friendship, and growing up. It features beautiful animations, catchy songs, and memorable characters that will captivate both children and adults alike.