10 Stargate Storylines That Were Never Resolved
3. Did Anyone Return To Take On The Wraith?
In the series finale of Atlantis, the miraculous (read as: the show was cancelled and they needed to wrap up the journey) invention of 'wormhole drive' is created by McKay, allowing the city ship to transport to Earth's orbit to destroy a ZPM powered Wraith Hive ship and save the day.
While the entire deus ex machina ending of that episode was simply accepted by the people involved - what happened to the Wraith Hive Ships that were still operational in the Pegasus galaxy?
The Atlantis expedition, entirely accidentally, is responsible for unleashing the Wraith on that galaxy again, as it was they who woke the Wraith early. Their escape to the Milky Way galaxy was a fantastic escape for them - but it then leaves the rest of the humans in the Pegasus galaxy to the mercy of the Wraith - a species who are not well known for their mercy.
By the series' close, there are still around twenty active Hive ships in the galaxy...someone really should do something about them!