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.

To save millions of lives, medical martyrs have put themselves in the line of fire. Eighteenth-century obstetrician Ignaz Semmelweis plants the seeds for germ theory before a stunning downfall. Peruvian hero Daniel Carrión chases down a deadly disease using a dangerous experiment. Deep-diving inventor Sieur Freminet plays a lethal game of trial and error as he tests out his revolutionary diving suits.

Intrepid explorers have ventured into the world’s most unforgiving landscapes in a relentless quest for knowledge. Biochemist Peng Jiamu braves the shifting sands of China’s northern desert in search of its hidden secrets. In the 18th century, Jean-Francois Laperouse sails into the remote Pacific, determined to find the elusive Northwest Passage. Ancient Roman scholar Pliny the Elder confronts the wrath of Mount Vesuvius to harness the wisdom of the natural world.

Examining molecules, compounds, and chemicals, scientists take risks on great discoveries. Carl Wilhelm Scheele uncovers the stuff of life as he tinkers with deadly substances. Rosalind Franklin gives humanity the first image of the double-helix, but her contribution seems to fall by the wayside. Against all odds, female chemist Alice Ball develops the cure for leprosy, though a twist of fate means she’ll never see its impact.

Tinkering with the unseen can have dangerous consequences. As lightning flickers over St. Petersburg, a 19th-century physicist attempts to harness electricity. In an ultra-secret lab, a Canadian scientist brings a dangerous nuclear reactor to the edge of annihilation as part of the Manhattan Project; and, as an astronomer observes distant star formations in the darkest lab on earth, he is suddenly struck by a mysterious illness.