"Todd" (Christopher Heyerdahl) informs Atlantis that a group of Wraith have multiple ZPMs and they plan to use one of them to power a new super Hive Ship.

"Todd" urges the expedition to destroy it, but when the team reaches the hive, they realize that the ZPM has already made the ship far more powerful than expected, and causes significant damage to Daedalus before jumping into hyperspace.

The team then finds out that the Hive has picked up a subspace transmission from the alternate reality depicted in "Vegas", giving the Wraith the location of Earth.

However, before their plan of fitting nukes on the F-302s is complete, they discover that the ship has already arrived, and is sending a large squadron of darts, which perform a kamikaze run into Area 51, destroying the Antarctic Ancient control chair, and ZPM losing hope of using the Antarctic drone weapons against the ship.

Woolsey (Robert Picardo) sends Teyla (Rachel Luttrell), Ronon (Jason Momoa), McKay (David Hewlett) and Lorne (Kavan Smith) to the Hive to destroy it.

[1] The shooting of "Enemy at the Gate" overlapped with "Vegas", which was not unusual as Atlantis used to film multiple episodes at the same time during its run.

The producers had wanted the city to come down on Earth near a recognizable landmark, as to be different from the previous five years of the show where Atlantis was always located in the middle of the ocean.

Martin Gero and Carl Binder were insistent that it should be the Statue of Liberty, but the geography was not plausible enough for leaving the city cloaked for any length of time without anyone noticing and/or getting killed.

[4] Although the producers knew of Don S. Davis' (George Hammond) heart problems, his death "came as a total shock" to them.

[8] In the UK, the finale was viewed by 633,000, placing Stargate Atlantis third in the top ten for Sky1 in that week, behind The Simpsons and season seven premiere of 24.