High above the Replicator homeworld, a provisional alliance wages an all-out assault on the Replicator fleet. As the battle wages, a group of wraith execute a last-minute plot to retrieve a ZPM from the planet's surface. Weeks later, the Atlantis long-range sensors detect the signal of a subspace tracking device familiar to Dr. McKay. The team follows to signal to a damaged hive ship drifting in space. Amidst the ship's records, they discover references to a secret wraith base...
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