Lachlan Smith is still grieving the loss of his father and adjusting to a new home in a new town. When he investigates a strange noise in his room, he discovers a portal to another world—or so it seems. Passing through it, Locksmith and his new friend Gary Thalberg find that this is their own world, in the future… and that it has been uninhabited for decades. The human race has gone extinct. Lock and Gary don't think of themselves as heroes, but this is a situation that calls for action. So they set out to explore the empty world, facing all its dangers to learn what happened—or will happen—and prevent it. But Lock, introverted and secretive to a fault, is determined to keep anyone else (especially his overbearing mother and older brother) from finding out about the portal. In the end, he will have to reach out to others and figure out who to trust—and who not to trust, because his family has an enemy who will go to any length to take their house and the portal for himself.

When 12-year-old Lachlan Smith found a portal to a hundred years in the future, he discovered a world where the human species had been extinct for decades. Now Lock and a small group of his friends and family are exploring the ruins of the future to learn its secrets. At the same time, they're trying to keep those secrets from the world of the present and prevent the time portal from falling into the wrong hands… all while maintaining the semblance of a normal life. The more they find, the more they realize that if they're going to prevent the end of the human race, they can't do it by themselves. But who can help them? And who can they trust with the portal and the power it represents—the power to reshape the future… or destroy it? For Locksmith, new discoveries, hard choices and dangerous journeys await.