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This story contains MODERATE SPOILERS for the upcoming fourth season of "Stargate: Atlantis."

What will happen to the Atlantis crew as their city drifts in space, their shield ready to crumble?

Well, we know they won't die because then it would be a rather short fourth season. But "Stargate: Atlantis" will lose a star while gaining another.

The show is set to premiere Sept. 28 on SciFi Channel with its fourth season premiere "Adrift," according to GateWorld. Just like the name implies, the city is still adrift in space and the shield is about to fail. Dr. McKay (David Hewlett) is trying to save the city while the medical team tries to save Dr. Weir's (Torri Higginson) life.

Samantha Carter (Amanda Tapping) makes waves on the show Oct. 5 with the episode "Lifeline" when she takes the Apollo in a "race against time" to find Atlantis, which has gone missing after the Replicator attack of the third season. Col. Sheppard (Joe Flanigan) takes a team to try and steal a ZPM from the Replicators.

In "Reunion" on Oct. 12, Ronon's (Jason Momoa) people return, and want him to help them raid a Wraith weapons facility. But there is more than meets the eye, as an enemy emerges that no one ever expected.

After "Doppelganger" airs Oct. 19, a new alien race is introduced Oct. 26 called the Travelers in an episode of the same name. Col. Sheppard ends up a prisoner on their generational ship, and they don't want much. Just Ancient technology.

New episodes of "Atlantis" will continue through Thanksgiving in the United States including "Tabula Rasa" on Nov. 2, "Missing" on Nov. 9 and "The Seer" on Nov. 16. Two episodes follow the holiday with "Miller's Crossing" on Nov. 30 and "This Mortal Coil" serving as the mid-season finale. But don't expect a big break between the finale and the mid-season premiere, as the show will take a similar route to "Battlestar Galactica" last season and air "Be All My Sins Remember'd" right after the Christmas break on Jan. 4, followed by "Spoils of War" on Jan. 11, "Quarantine" on Jan. 18 and "Outcast" on Jan. 25. There will be no off-weeks (at least so far) during the second half of the season as new episodes are expected to run all the way to the March 7 yet titled season finale.

"Stargate: Atlantis" airs Fridays at 10 p.m. ET on SciFi Channel while Movie Central in Canada will begin airing episodes Oct. 1, and Sky One in the United Kingdom will premiere the season Oct. 9.

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