In some ways the Galactica story is advancing at hyperspeed through this episode, which begins with the arrival of the Cylon base star in the middle of the human fleet, and ends with the base star’s abrupt disappearance — with President Roslyn and Gaius Baltar aboard.
In between, Gaeta loses part of his right leg and sings to console himself; the humans plot to deceive the Cylons once the “five” are identified; the Cylons plot to deceive the humans at the same moment; Roslin discovers Tory’s affair with Baltar; and Sharon/Athena kills the Rebel Six in an attempt to prevent the shared vision from coming true.
Meanwhile, the alliance with the Cylon rebels forces the Tigh, Tyrol, Tory and Sam to fret about being discovered as Cylons. Tigh, in particular, is agitated about the possibility of being discovered.
At the risk of seeming oversimplistic, the entire show can be boiled down to a search for identity. The humans are searching for their roots on Earth; the Cylons are searching for their place in the universe; and the four Galactica Cylons are searching for the own personal identities. Are they human, machine or something else?