Angler Jeremy Wade normally travels into the most remote regions searching for freshwater monsters, but recently he's been getting reports of killers from an unexpected location. This two-hour special follows Wade's investigation of America's killers.

Jeremy Wade takes on Africa's wild Zambezi River to unmask an invisible predator that's dragging fisherman to their deaths. Crocs and hippos are guilty of killing many in plain view, yet it seems there's another monster stalking these deadly waters.