When a daring mission leads a deep sea submarine team into a mysterious opening on the ocean floor, they uncover a lost underwater world and awaken its ancient race of otherworldly beings.

The Chipmunks and the Chipettes go head to head in a hot air balloon race, and the winner gets $10,000. Unbeknownst to the participants, the "race" is actually a diamond smuggling ring!

When monsters suddenly appear from the bottom of the Atlantic Ocean, a special team pilots giant robots to combat the new threat.