Littlefoot befriends with a mysterious, fun-loving dolphin-like creature named Mo, who is trapped in "new water" caused by heavy rain. The gang then goes on an adventure to the "big water" to bring Mo home.
| Actor | Role |
|---|---|
 John IngleNarrator / Cera's Dad (voice) | Narrator / Cera's Dad (voice) |
 Kenneth MarsGrandpa (voice) | Grandpa (voice) |
 Miriam FlynnDiplodocus Mom / Grandma (voice) | Diplodocus Mom / Grandma (voice) |
 Thomas DekkerLittlefoot (voice) | Littlefoot (voice) |
 Anndi McAfeeCera (voice) | Cera (voice) |
 Aria Noelle CurzonDucky (voice) | Ducky (voice) |
 Rob PaulsenSpike / Mo (voice) | Spike / Mo (voice) |
 Tress MacNeilleDucky's Mom / Petrie's Mom (voice) | Ducky's Mom / Petrie's Mom (voice) |
 Jeff BennettPetrie (voice) | Petrie (voice) |