Dr. Weir is reborn, and Dr. McKay tries to save Atlantis, which has been devastated by the replicators. The available energy can only last for 24 hours, and the Stargate cannot be used. Can the Atlantis team defeat the end of the world again? McKay and Sheppard plan to take back ZPM from the replicators. At the same time, Samantha Carter and Apollo are looking for the legendary lost city - Atlantis. Will McKay's plan succeed? Can Carter find the location of the lost city?