The Aldens travel to Australia to learn about protecting the Great Barrier Reef and the animals that live there.

Henry, Jessie, Violet, and Benny are going down under. Off the coast of Australia, they dive in to explore the Great Barrier Reef. With the help of their conservationist guide, Kayla, they learn about ways to help rebuild the damaged reef. But coral reefs take a long time to take shape. Can the Aldens find ways to help the animals that need help now?