Season synopsis
Contains spoilers for this season and earlier seasons.
Four fleet members have been revealed as Cylons when Kara Thrace returns in a pristine Viper, claiming she can lead the fleet to Earth. Adama gives her the Demetrius and a search crew; they strike a dangerous bargain with rebel Cylons. Their joint attack destroys the Resurrection Hub, ending the enemy's ability to revive dead models. Meanwhile, Cally learns her husband, Chief Tyrol, is a Cylon. Tory Foster kills her, and the death is reported as suicide, adding another breach of trust within the fleet.
D'Anna Biers demands the Final Five, forcing Tigh, Tyrol and Anders to reveal themselves while Tory secretly joins the rebel Cylons. Adama grants the four amnesty and shares the fleet's knowledge of Earth. Kara's Viper supplies a bearing, and the ships reach the planet the Thirteenth Tribe called Earth, only to find a radioactive wasteland. With that destination lost, Adama considers admitting Cylon technology and people into the fleet. Felix Gaeta and Tom Zarek turn opposition to the alliance into a mutiny that puts Galactica and the government under threat.
The mutiny collapses after Zarek has the Quorum killed and Gaeta loses control of Galactica; both leaders are later executed. Ellen Tigh returns as the fifth Cylon. The fleet's alliance continues as damage to Galactica worsens and Cavil's faction takes Hera to its Colony. A final assault rescues her and destroys the Colony. Kara uses the Final Five's music to find a route to a different, habitable planet and jumps Galactica there. Roslin dies after reaching it with Adama. The Colonials and their Cylon companions choose to settle there, name this world Earth, and send the fleet's ships into the Sun. Kara disappears; a distant-future coda identifies Hera as the maternal ancestor of modern humanity.