Ba'al sends his fleet back to retake the planet Dakara, pitting his ships against Teal'c and the Jaffa. The RepliCarter tries to probe Daniel's mind to find all the Ancients' knowledge, while Jacob and Carter discover the Ancient weapon on Dakara and try to figure out how to use it to destroy the Replicators.

SG-1 and General O'Neill use the time traveling puddlejumper to go to Ancient Egypt to recover a ZPM. They successfully steal it, but something is wrong and the future is altered to that the Stargate program never happened. Daniel, Sam, and Jack must find a way to save their reality despite never having met before.