S5·E4 The Daedalus Variations

The Atlantis expedition mysteriously finds the Daedalus, abandoned and drifting in space. When Lt. Colonel John Sheppard's team come to investigate, the ship mysteriously disappears. They soon discover that the ship is actually an alternate Daedalus from a Alternate reality, and the team must find a way back to their Universe or risk being stranded forever in an unfamiliar reality.