When aliens ‘unmake’ the human race, in order to protect the universe from war, they elevate the canine family of species to be the new dominant life on Earth. This involves gifting dogs, wolves, foxes and all the other Canidae the ability to converse, as well as to enjoy a higher consciousness. Cerberus follows one group of dogs as they come to terms with this new state of being, revealing their developing logic, their humour and their sense of wonder. It also tells of their adventures, as they assist the aliens in an uncertain quest to capture fugitive human leaders regarded as dangerous to peace amongst the stars. This quest is led by Garth, a much-abused mastiff who has been rescued from an animal laboratory. Garth is able to communicate with the aliens, an ability that endows him with respect among the dogs as well as other canines they meet. But all along, Garth has to overcome his suspicions that he is being manipulated by the aliens rather than assisted by them. This puzzle eventually comes to a head when they persuade him to attempt a final mission, pitching him against a growing force in the ruined forests of eastern Europe. Faced with a choice between acquiring power or defeating it, his decision has a cataclysmic outcome.