Mark Evans travels to Namibia's Chobe River, a place that's known as the croc attack capital of the world. Crocodiles here are growing in size and number, and so is the frequency of attacks. Each time it happens, the locals kill crocs in retaliation. To find a way to keep both people and crocodiles safe, Mark joins leading croc experts Rom Whitaker and Dr Patrick Aust to carry out a radical new experiment. The idea is to train crocs to associate the sound of a bell with an electric shock. Mark meets attack victims, puts the croc training experiment to the test and is himself injured when a croc turns on him.