Lachlan Smith doesn't think of himself as a hero. His father lived a heroic life, and died an even more heroic death. Locksmith has no ambitions to do the first, and absolutely refuses to do the second. But everything changes when Lock and his friend Gary investigate a strange noise in the closet of his new bedroom... and discover a portal to another world. It is a vast, steaming jungle, full of ruins and devoid of all human habitation. It is a dangerous world with many predators, from giant feral dogs to swarms of hungry rats. It is our world, many years from now, when the human species has gone extinct. Lock and Gary experiment with the portal, and find that by making small changes in the present, they can alter the future. But can they make the biggest change of all? Can they discover what happened -- or will happen -- in time to prevent it? Lock and Gary are not heroes -- yet. But the adventure they have chosen will test them as they have never been tested before. They'll need all their intelligence, courage and will to save themselves.