When Atlantis's deep-space sensors detect the Aurora, an ancient Atlantian warship, at the edge of the galaxy, Sheppard's team wastes no time hitching a ride to it aboard the Daedalus. Upon their arrival, they encounter a Wraith scout ship. They destroy the scout before it can cause trouble - or so they hope.
Sheppard leads his team onto the derelict warship, where they discover hundreds of crewmembers frozen in stasis pods. Although technically alive, the Atlantians are thousands of years old, and their aged bodies can't survive the defrosting process. Still, there might be a way to talk to them: McKay discovers that all the pods are linked by an active neural interface, allowing the crew to coexist with each other in a virtual environment.
Eager to chat with these survivors from the distant past, Sheppard enters an empty stasis pod and McKay connects him to the interface. Sheppard immediately finds himself aboard a fully powered Aurora. To his surprise, the Atlantians there treat him like an intruder and toss him in the brig.
The Aurora's captain is intrigued by Sheppard's story, but doesn't remember entering a stasis pod, doesn't believe that his world is a computerized fiction, and certainly isn't convinced that 10,000 years have passed. Instead, he and his single-minded first officer apparently believe that they're still in their own time. They're racing to upgrade their ship's hyperdrive engines so they can reach Atlantis quickly and deliver vital intelligence about a critical weakness in the Wraith's defenses.
Back in the real world, the Daedalus's sensors spot two Wraith cruisers heading their way. They'll arrive in just over an hour. Then Ronon and Teyla make an even more chilling discovery: One of the stasis pods contains a Wraith. He has hacked into the neural interface and must be posing as a crewmember within the virtual environment.
McKay enters the virtual world and warns Sheppard of the impostor. The two must win the captain's trust and root out the Wraith, and not just to save themselves. After all, by spying on the hyperdrive modifications, the undercover Wraith can learn how to build much faster intergalactic ships. If Sheppard and his team can't stop this virtual espionage, the Wraith will soon be able to travel between galaxies and attack the richest feeding ground of all - Earth.