S1, E1: In a rapidly vanishing habitat on Brazil's Atlantic coast, the largest venomous snake in the Americas is on the verge of extinction. During months of drought, the Bushmaster has hidden from sight, and reptile hunter and scientist Mark O'Shea is in a race against the clock to capture the rare and deadly rainforest dweller and extract its venom. But it isn't known as The Ox-Killer for nothing.