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Tigh, Anders, Tyrol and President Roslin's assistant Tory Foster are all now hearing — or hallucinating — a strange song aboard the Galactica.
Roslin, meanwhile, is recovering in the ship's infirmary after her first major cancer treatment. There, she experiences another vision of the opera house through which she, Athena and Six pursue the toddler Hera.
Waking with a start, Roslin is shocked to discover that Six, Athena and Hera have shared the identical vision. Like those hearing music, none of these women can find an answer for their perplexing experience.
At Baltar's trial, the defense is teetering on the edge of defeat. To save his client, Romo Lampkin moves for a mistrial because Lee Adama has heard his father — a judge — make biased statements against Baltar in private.
Lee reluctantly takes the witness chair. Instead of admitting his father's prejudice, however, he makes a compelling speech on behalf of his client, arguing that President Roslin has forgiven countless misdeeds since the fleet's long journey began, and Baltar should be treated no differently.
Lampkin rests his case after this eloquent statement, and soon, the judges determine by a vote of three to two that Baltar cannot be considered guilty. The courtroom erupts into chaos. The last duty that Lee and Lampkin perform for their client is to whisk him away from the mob to safety. After that, Baltar is a free man — but he's also on his own in a hostile fleet.
Roslin is disgusted with the verdict, and her relationship with Adama is shaken when she learns that he voted to release Baltar. They must set aside their conflict, however, when the fleet finally arrives at the Ionian Nebula.
As the Galactica scans this waystation on the route to Earth, the entire fleet abruptly loses power. In the darkness and confusion that follow, Tigh, Tyrol, Tory and Anders are nearly overcome by the insistent song, and they each follow it to an obscure workout room on the Galactica. When they lock eyes with each other, they guess the obvious but horrifying explanation for the mental summons that they've obeyed: they must all be Cylons.
At that moment, a massive Cylon armada bursts onto the scene. Lee Adama joins his old Viper crew and flies out in defense of the Galactica. In the light of the mysterious nebula, to his shock, Kara Thrace appears in a Viper next to him. Seemingly back from the dead, she has come bearing a message of cosmic importance….