“Rising: Part 2” is episode two of season one of Stargate: Atlantis.
In the previous episode, “Rising: Part 1”, the lost city of Atlantis had been discovered and a team sent there. Unfortunately, the city’s power was almost depleted and, given that it was submerged below the ocean and solely protected from the ocean by a forcefield – which requires power to work – this was not good. In an attempt to ensure their safety, teams were sent through the city’s stargate, looking for alternate places to settle. On one world, they encountered an alien ship, inhabited by beings called the Wraith.
Although the city’s forcefield has failed, Atlantis has risen back to the surface, making it fairly safe to live there. Unfortunately, the Wraith that they encountered are the enemy that defeated the Ancients and, without power, the city is largely defenceless. Some of the exploratory team have been captured by the Wraith, so Major Sheppard takes a rescue team to try and free them. Which has some unforeseen, and really bad, consequences.