Adama and Roslin fight for the hearts and minds of the fleet's population, as Starbuck finds herself trapped in a supposed resistance hospital.

Adama plans to return to New Caprica and drop off a surprising person to act as a liaison between Galactica and the Resistance. Tigh's insistence on the use of suicide bombers and ever escalating violence stuns even the fellow leaders of the Resistance. Eventually, the suicide bombings cause the Cylon occupiers to crackdown on their human subjects.

Sharon helps the Resistance on New Caprica as Adama leads Galactica on a dangerous rescue operation. Tyrol races to save Cally from the execution squad. Meanwhile Anders uncovers treachery among the humans. Number Three meets the Oracle Selloi after having strange dreams about the temple.

Tigh must decide the fate of his wife Ellen after the assistance she rendered to the Cylons. Lee struggles with his assignment to protect the civilian fleet on its journey toward Earth while Adama returns to New Caprica with just the Galactica. The Resistance coordinates an attack on the Cylons just as Galactica arrives. As the Cylons begin to lose control, Number Three vows to put a final end to the New Caprican experiment.

Lingering feelings of rage lead Saul Tigh and Kara Thrace to cause problems aboard Galactica between the survivors from New Caprica and those who stayed with the fleet during the Occupation. Baltar assists the Cylons in an attempt to stay alive and uncovers details about Cylon civilization. A Cylon baseship falls victim to a mysterious disease.

Apollo formulates a plan that threatens the very existence of the Cylon culture. Adama and Roslin must decide whether to follow through on the plan to use a biological weapon against the Cylons. D'Anna Biers (Number Three) believes Baltar knows who created the virus that infected and disabled the Cylon baseship. She is willing to take extreme measures to learn the truth.

The Cylons learn that the Final Five are in the Colonial fleet. Some of the Cylons want the Cavil model to stop lobotomizing the Raider ships. Starbuck desperately tries to convince the others that the fleet is going the wrong way in their search for Earth.

With Galactica on the verge of falling apart, Admiral Adama readies the ship for what could be its final mission, as Baltar's Six warns that humanity's final chapter is near.

Adama and the Galactica crew stake the survival of the human race on their plan to rescue Hera from the Cylon colony in this, the series finale.