In the heart of the tropical island of Papua New Guinea is a giant volcano, long since extinct and covered in dense jungle. No one knows what creatures hide in its deep crater, trapped from the outside world by walls a kilometre high. Now an international team of scientists have joined with wildlife filmmakers from the BBC's Natural History Unit. They discover some of the strangest creatures on Earth, from talking beetles to the world's smallest parrots and even a giant rat that's the size of a cat. In just four tough weeks they find over forty species of animals never known before.