The following story contains MODERATE SPOILERS for the fourth season of SciFi Channel's "Stargate: Atlantis."

"Stargate: Atlantis" other enemy is back for Season 4.

You know, the Replicators. Artificial life forms composed of trillions of microscopic nanites created by the Ancients originally to combat the Wraith, but instead turned on them. But dont worry, the Atlantis writers arent going to just replicate the same plot all over again. No, this time there will be a couple of new twists.

David Hewlett, who plays Rodney McKay in the SciFi Channel series, told GateWorld to expect "lots more hands in foreheads and things. And twists on that as well."

"It's funny -- [executive producers] Joe [Mallozzi] and Paul [Mullie] were really excited about, I think, playing with the established stuff," Hewlett said. "Leading people to believe things are going to be like they were, and then throwing them a curve. There's some great use of that, especially with the Replicator stuff, where the Replicators are getting stuff thrown back at them that they're not expecting. We fight back in weird and devious ways."

When we last left the Atlantis team in the Season 3 cliffhanger, they had fired up the stardrive and flew the city into deep space to escape Replicator retaliation with a satellite weapon. But unexpectedly the city ran out of power and became stranded deep in space. The Atlantis team didnt escape the Replicators though. They will be back in the first two episodes -- "Adrift" and "Lifeline" -- of Season 4. Returning to lead this powerful threat is Oberoth, played by David Ogden Stiers (who can also be seen playing Rev. Gene Purdy over on The Dead Zone).

Stopping these deadly nanite foes becomes trickier each time. But the Atlantis team has some new plans. Hewlett explained that :there's a neat twist on that at the beginning of the season as well where we use a bit of the old Replicator tech for good as opposed to evil. And I think [it] establishes a very interesting possible character arc for one of our regulars."

The Stargate Atlantis Season 4 premiere will air Sept. 28 at 9 p.m. ET on SciFi Channel.

VOTE NOW! The polls are open for the 2007 SyFy Genre Awards! Cast your ballot now!