From birth to weaning, from territorial disputes to courtship and mating, from brush fires to drought, gum trees are what determine a koala's success or failure, survival or mortality. This film will explore the remarkable bond between the koala and the eucalyptus trees it so depends upon. By following individual koalas from a small social group on an Australian island, NATURE will reveal just how a koala manages to survive and thrive on a diet poisonous to almost all other herbivorous mammals.