Set sail on a revolutionary mission with the world's leading blue whale researchers. Supported by the National Geographic Society, Dr. Joe Roman and Dr. James McCarthy, along with an international team of scientists, embark on the tallest order of whale research. The team must find, identify, and tag California blue whales in order to collect crucial DNA samples that confirm the sex of each individual whale. The research party reunites with the blue whales' impressive migration pattern at a unique gathering place in the sea, the Costa Rica Dome.