Our human senses are pretty incredible - but we only see, hear and smell a tiny fraction of what's out there. There is a hidden world that animals across the globe can experience. In this episode we explore thepowerful world of scent and the animals that have pushed their sense of smell far beyond human abilities. In the Bahamas, Helen dives into shark-infested waters with only a small pouch of liquid as her defence. Patrick controls the behavior of a swarm of bees using tiny traces of scent and he gets uncomfortably close to one of the smelliest animals in the world - a skunk!