The Land Before Time III: The Time of the Great Giving starts with Littlefoot and his friends, Cera, Ducky, Petrie, and Spike, playing a game of "Follow the Leader." The game quickly turns into a race, and Littlefoot ends up taking a shortcut through a narrow passage. However, as he comes out of the passage, he accidentally bumps into Hyp, Nod, and Mutt, who were sleeping nearby.
Hyp, Nod, and Mutt wake up in a foul mood and start bullying Littlefoot and his friends. Later that day, the inhabitants of the Great Valley witness a shower of meteorites that impact near their home. The meteorites cause a rock slide in the Mysterious Beyond, which blocks the water supply of the Great Valley.
As a result of the blocked water supply, the inhabitants of the Great Valley start to experience water scarcity, and tensions rise between different groups of dinosaurs. Littlefoot and his friends, along with some of the older dinosaurs of the Great Valley, try to find a solution to the water scarcity problem. However, Hyp, Nod, and Mutt take advantage of the situation and create havoc in the Great Valley, stealing water and causing more conflicts.
In the end, Littlefoot and his friends come up with a plan to unblock the water supply, which is successfully executed, and the water flow is restored to the Great Valley. The solution to the water scarcity problem brings the inhabitants of the Great Valley together, and peace and harmony are restored.
Throughout the movie, there are themes of teamwork, friendship, and the importance of banding together during tough times. The Land Before Time III: The Time of the Great Giving is an entertaining movie for children, but it also imparts valuable life lessons.