Studying Earth's creatures can yield profound scientific insights, but meddling with the natural world can have lethal consequences. Snake enthusiast Kevin Budden risks everything in his pursuit of Australia's most venomous reptile. While expanding our catalogue of birds, ornithologist John Cassin plays with poison beneath their plumes. One of Britain's greatest entomologists, Harold Maxwell-Lefroy, falls victim to the very insecticide he hopes will safeguard the world.