Everyone on Atlantis is shocked when the Daedalus, which is supposed to be en route to Earth, suddenly appears in orbit above the city. Sheppard and his team go aboard and find their doubles, all dead. McKay concludes that the ship is from an alternate dimension and in the wink of an eye, they are transported to an alternate reality. The first jump has them trying to figure out where they are while McKay tries to determine why the ship is acting as it is. Their second jump sees them under attack from an unknown race and the third jump has them too close to sun and under risk of being burned up. McKay concludes that the only way they will ever again see their own Atlantis is to travel back through each of the jumps they have just made.