Philippe and Ashlan Cousteau uncover new leads in the search for pirate Calico Jack's missing treasure that could be worth $250 million. Their mission reaches a stunning climax during their high-risk scuba dive beneath waves.

Philippe and Ashlan Cousteau head to St. Thomas to learn more about Jean Hamlin, a sadistic pirate who may have left a vast fortune on the sea floor. Their investigation uncovers a secret society of divers who lead them to a shocking discovery.

Ashlan and Philippe Cousteau head to Bermuda to help solve the mystery the Roanoke, a Civil War-era gun runner that was taken over by pirates. In more than 150 years, no one has been able to find the doomed vessel and its mysterious cargo.

Philippe and Ashlan Cousteau return to the US Virgin Islands to investigate what happened to the RMS Derwent, a 19th-century paddle wheeler that vanished without a trace. Recent hurricanes have revealed clues to the boat's whereabouts.