Locksmith's Closet, by Paul Briggs

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? And where did the portal come from? Why is it in his closet? Why did the previous owner of this house disappear without a trace? And who is the strange man who has made himself an enemy of Lock's family, insisting that the house belongs to him and that he will stop at nothing to get 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 — and everybody else. Please note: Member price includes shipping. Paul is happy to inscribe and autograph this for you. Just include a note as to whom you'd like the book inscribed.