Steve Backshall and the Deadly 60 crew head for the island paradise of Sri Lanka. First they head to Yala National Park, famous for its population of one of the most elusive and cryptic cats on the planet - the Sri Lankan leopard. The team then set up a night-time stakeout in a local village to try and film an ancient river monster, the mugger crocodile. And the night-time deadlies don't stop there when a local brings an enormous, bone crushing Indian rock python to Steve's attention. Finally it's a mission of massive proportions as Steve attempts to free dive with the largest animal ever known to have lived, the blue whale. It's a lifetime ambition, with some jaw-dropping results.