Dan O'Neill joins Dr. Juliana Terra, a herpetologist in Southern Brazil, hoping to track down a giant female green anaconda during the mating season; the snake's natural camouflage complicates the task.

Dan O'Neill searches for the biggest living elephants; he learns about their ancestors, explores their evolutionary secrets, and discovers ways to protect the giant elephants of today.

Dan joins Dennis, an indigenous saltwater crocodile guide in Australia's Northern Territory, hoping to track down a legendary giant male lurking somewhere along the Mary River.

Dan O'Neill joins marine scientists Charlie and Lauren on their expedition as they set off to the Neptune Islands in South Australia, hoping to find a giant great white lurking somewhere beneath the waves.

Dan O'Neill learns about the biggest cat to ever exist so far, explores the lions' evolutionary secrets, and finds out ways to protect the modern lions.