The team is in the crystal-clear waters of Bimini in the Bahamas to witness the incredible journey of the great hammerhead shark; as the team follows the shark's migration, they discover the secrets of how these animals navigate the vast ocean.

The team travels to the Dominican Republic in the Caribbean to reveal the greatest secrets in the lives of the North Atlantic humpback whale; they witness a mother defend her calf in the ultimate ocean battle with a pack of orcas.