For years fishermen have been vanishing in Alaska's remote and unforgiving wilderness - their deaths unseen, their bodies never found. For freshwater detective Jeremy Wade, a recent fatal incident sends him on a search for possible suspects.

Jeremy Wade returns to Africa's Okavango Delta to investigate a pack-hunting carnivore blamed for mauling the victims of a capsized boat. This time, Jeremy decides to put on his dive gear and offer himself as live bait in croc-infested waters.