By following individual koalas from a small social group on an Australian island, we will reveal just how a koala manages to survive and thrive on a diet poisonous to almost all other herbivorous mammals. From the miracle of marsupial birth to tender moments of discovery between mother and newborn joey, encounters with threatening forest creatures, battles between rival males and the complex chorus of bellows and grunts that have become so important to science, we will join leading scientists as they unravel just what a forest needs to support a healthy population of koalas by listening to these marsupials themselves and cracking the koala code.