The Land Before Time IX: Journey to Big Water (2002)

Plot
After a period of harsh rain, the Great Valley is partially flooded and covered in debris. Littlefoot tries to play with his friends, but they are preoccupied: Cera and her father are removing a large log from their nesting area, Ducky and Spike are relocating their nest with their family, and Petrie has gotten a cold. A bored Littlefoot wishes for a brother, but eventually explores on his own and discovers a large area flooded by the rains. The adults advise their children to stay away, fearing that dangerous creatures from the outside may have been washed into the Valley. However, Littlefoot returns and meets Mo, a playful young Ophthalmosaurus that had been caught in the floodwater.

Littlefoot quickly strikes a friendship with Mo and describes him as his mud brother. His other friends also eventually befriend him. Mo explains that he is from the Big Water, and he swam into the Valley during the flooding. He confirms that he is alone, but soon after, a Liopleurodon attacks the group. Littlefoot requests help from the adults to help Mo return home, but they refuse, not wanting to risk leaving the Valley to aid an outsider. A subsequent earthshake separates the children and Mo from the rest of the Valley, but it also imprisons the Sharptooth in an underwater cavern. Unable to return, they decide to take Mo home on their own.

The children follow a river that they believe leads to the ocean. A Diplodocus mother allows them to take refuge at her nest for the night, and the friends are present to witness the hatching of her offspring. The next day, Littlefoot and the others realize that they are near the ocean, as they have begun to taste salt in the water. However, the Sharptooth – who has escaped from the cave – attacks them that night. The land – which surrounds the river – is steep and slick with mud, and the children are unable to escape. Mo distracts the Sharptooth and lures it further down the river. Reappearing the next day, Mo explains that the Sharptooth had smelled the ocean in the distance and abandoned the chase, choosing to return to the sea.

The children reach the ocean, but Mo is saddened to learn that his friends must depart. He wishes to remain with them, but the others explain that he cannot, and Littlefoot reminds Mo that the two will always be brothers. Mo reunites with his family and asks them for directions to the smoky mountains, as the children know how to find the Valley from that location. Before leaving, Mo offers to show Littlefoot his home. Littlefoot accepts the offer, and is amazed by the underwater world's beauty. Littlefoot and his friends say goodbye to Mo and return home, where they are greeted by the adults.

Voice

 * Thomas Dekker as Littlefoot
 * Anndi McAfee as Cera
 * Aria Noelle Curzon as Ducky
 * Jeff Bennett as Petrie
 * Rob Paulsen as Spike / Mo
 * Kenneth Mars as Grandpa Longneck
 * Miriam Flynn as Grandma Longneck / Diplodocus Mom
 * Tress MacNeille as Ducky's mother / Petrie's mother
 * John Ingle as Narrator / Topsy