With the arrival of the Apollo to Atlantis comes intel that the Replicators appear to be building a large armada to directly attack earth. Planning to strike first, Col. Ellis with the aid of the Atlantis team launches a surgical strike nuking the entire armada. Believing that all imminent danger has been avoided the team is shocked when a satellite housing a stargate takes up geosynchronous orbit above Atlantis. Unable to destroy the Stargate, it opens transmitting a powerful energy beam impacting Atlantis' shields. Being powered from the point of origin, neither the beam nor the satellite's shields show any vulnerability to the Apollo or Atlantis. Without any way of avoiding the beam as it quickly drains the ZPM powering the shields, Rodney McKay opts to sink the city as the ancients did millennia ago using the water to dissipate the beams strength. But when the sinking of the city doesn't have the desired effects, it appears it's only a matter of time before the shields fail. With the stargate active in such close proximity, it renders the city's gate inactive. Their only hope is to use what energy the ZPM has left along with strategic cover by an asteroid to hopefully fly the city into hyperspace before the shields collapse. But when the asteroid fails to hold, allowing the beam to cut through to the city, it seems unlikely Atlantis will make it off the surface in one piece.