During his many adventures for National Geographic, Herpetologist Dr. Brady Barr has come face to face with some of the largest and most dangerous predators in the world. Now he is on a quest to shed light on a true mystery of the deep, the elusive Sixgill shark. Brady braves ocean depths in Honduras, extreme cold in Puget Sound and fearsome predators in Hawaii. His goal is to understand why this little known animal that normally lives in waters up to 8000 feet deep occasionally is found in much shallower seas. Brady's dream is to get as close to one of these creatures as he can and even swim with one. Will he be successful?