As Baltar's trial comes to a conclusion, key members of the fleet discover that they may be the Final Five Cylons. Tigh attempts to decipher the strange music he is hearing in his head, while a Cylon fleet approaches.

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.

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.

The struggle between Adama and Cain is temporarily put on hold while the two Battlestars combine forces for an assault on the Cylon Resurrection Ship. Apollo faces a momentous decision and Baltar takes an interest in Gina, the Cylon prisoner.

When Commander Adama learns that Kara disobeyed orders and Jumped to Caprica on orders from President Roslin, he demands the president's resignation, with the implied threat of a military coup. Roslin refuses his demand and sparks a confrontation.

Battlestar Galactica was not the only Battlestar to have survived the cylon attack, The Battlestar Pegasus also survived.

D'Anna holds President Roslin and other Colonials hostage in order to draw out the Final Five from the Colonial fleet. Col. Tigh believes he has the solution to end the standoff.

The Battlestars Galactica and Pegasus face a new Cylon target, a "Resurrection" ship, while a power struggle threatens to result in all-out war among the human fleet.

President Roslin faces off against Tom Zarek and Lt. Gaeta as they try to take control of the Colonial fleet. Both the alliance with the rebel Cylons and Adama's life are at stake.

When Baltar wins the vote, Roslin considers stealing the election because she believes he is a Cylon collaborator.

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.

Loyalties are made clear when Gaeta orchestrates a coup d'état of the Adama regime. Both prisoners and lives are taken as many of the fed up people work to take over Galactica.

Kara struggles with the foreboding prediction of the Cylon Hybrid, while Adama and the Colonial fleet face despair over their shocking discovery.

Sharon informs Adama that the Galatica has been infected with a computer virus that is tampering with the basic ship functions and is scanning them for weaknesses. All this is preparation for a major assault by the Cylon Raiders. So with the clock ticking, Commander Adama must pull himself together and decide: Can he trust Sharon?

When Lt. Kara Thrace goes missing in action after encountering a Cylon patrol while on a training mission, Commander Adama feels responsible — especially in light of her recent admission that she blames herself for his son Zak's death.

After Boomer's consciousness is downloaded into a new body following her death, she struggles with her new life on Cylon-occupied Caprica. Number Six is asked to help Boomer adjust to her new role in Cylon society.

Tyrol discovers the Temple of Five on the algae planet. The temple may hold the Eye of Jupiter, which is believed to show the way to Earth. The Cylons take a keen interest in the discovery. Athena learns that her baby, Hera, may still be alive. Lee relies on Anders to help build civilian support for the protection of the Eye. His relationship with Kara complicates matters.

President Roslin faces challenges as the Colonials plot with Cylon rebels to destroy a Resurrection Hub.

Adama heads to Kobol to find Roslin, reassembles the fleet and heads down to Kobol himself to find the presidential party in search of the "Tomb of Athena" which allegedly leads to Earth. Apollo hangs out with Starbuck , Zarek tries to keep his cronie off plotting with Boomer who is unaware of tension building between Helo and Tyrol.

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.

With Adama out of action, Colonel Tigh takes his position as commander of the Galactica. Boomer is in jail, and the cat's out of the bag - she's a Cylon.

As Sam Anders recovers from his head injury onboard the Galactica, he begins to remember events from ancient Earth. The Final Cylon struggles with the fallout from the Final Five's former plans. One of the humanoid Cylons vows to get revenge for being created in the image of Man. Tyrol informs Admiral Adama about the extensive structural damage on the Galactica.

Pegasus' new commander Fisk is murdered by black marketeers, and Lee is charged with solving the crime. Roslin seeks to stamp out the black market by introducing new trade regulations.

Adama stages a boxing tournament on the Galactica to help the crew relax. The competitive atmosphere sets off a brutal match between Kara and Lee. Flashbacks from New Caprica reveal the origin and nature of their dispute.

Chief Tyrol and his wife Cally become trapped in a malfunctioning airlock. Adama remembers his late wife Carolanne as he marks his wedding anniversary. His relationship with President Roslin continues to become more friendly and personal.

Gaius Baltar sets off a debate on religious freedom when he promotes his belief in a single God.

A woman takes hostages on Cloud Nine and demands that Adama turn over Sharon in order to avenge her husband's death at the hands of the Cylons.

President Roslin's fears that Commander Adama is a Cylon are stoked when she learns he's making secret wireless calls to other ships. Then, to make things worse, a single Cylon raider appears near the Galactica and begins acting strangely after being damaged in battle.

The Sagittarons allege that a doctor is discriminating against them. As Helo investigates, he becomes concerned that the doctor may even be murdering patients. Meanwhile, Athena unwittingly brings Hera to the doctor for treatment.

A crazed Cylon Raider attacks the Colonial fleet in a series of hit-and-run attacks. Overworked Viper pilots must defend a mining operation from this Raider that they nickname "Scar."

When Baltar and the Number Six who lives in his head have a falling out, she abandons him, only to surface a short while later aboard the Galactica. But now she's called Shelley Godfrey, everyone can see her, and she's telling them that she has evidence, passed on by the late Dr. Amarak, that will prove Baltar sold out the human race to the Cylons.

The Colonial fleet faces starvation when the food-processing machines are contaminated. Kat plays a vital role in the success or failure of the "Passage" through space.

Tigh and Number Six take their first glimpse at their unborn child, Tyrol offers Adama Cylon technology in return for his fellow Cylons properly reintegrated into the fleet, and an attempted coup leads to a costly struggle to maintain civility.

Now on board Galactica, Baltar faces charges of treason. He contemplates suicide with the help of Number Six. Questions remain about his true identity. Is he a Cylon or isn't he? Apollo shows off the new drinking establishment on Galactica, Joe's Bar, to Tyrol. Apollo thinks about Kara and wonders whether his marriage to Dee is worth saving.

When Baltar's representatives face assassination attempts, Adama asks Lee to protect Baltar's lawyer. After taking on the assignment, Lee seeks to play an active role in Baltar's defense.

Specialist Tyrol continues to sink into despair after his recent loss. He becomes curious about Gaius Baltar's sermons and the following he has attracted. The crew of the Demetrius grow concerned about Kara's mental stability as an old enemy arrives with a tempting offer.

When President Roslin calls an Interim Quorum of the Twelve Colonies, she discovers that democracy brings its ugly stepsisters — politics and deadly intrigue — to the party. Tom Zarek, the charismatic convicted terrorist, is elected as the delegate from Sagittaron and immediately proposes elections for the vice-presidency.

With President Roslin missing along with the cylon base ship a new president must be decided on. Galactica goes on a search for the missing base ship and the Galactica crew members that were on board.

Amid a heated labor dispute, Tyrol asks the imprisoned Baltar for advice. Seelix becomes involved after she is turned down for flight training.

Ellen escapes from Cavil only to face a momentous choice regarding the 13th Tribe and the Final Five Cylons.

A figure from Adama's past returns to haunt him. His return raises questions about why the Cylons launched their initial attack against the Twelve Colonies.

The fleet has found a source of water, but who will take on the difficult and dangerous job of mining it from the icy planet? Commander Adama and President Roslin send Lee to the Astral Queen, a prisoner transport ship, with an offer for its inmates: Volunteer for this mission and earn "freedom points".

As President Roslin nears death, Dr. Gaius Baltar must be groomed for the worst case scenario. Roslin orders the death of Sharon's unborn child. A sabotaged Viper leads to an investigation that uncovers a movement of people seeking peace with the Cylons.

When a new copy of Doral, a Cylon who had been previously exposed while serving as the Galactica's public-relations officer, sneaks aboard and blows himself up, killing three people, Commander Adama and President Roslin must finally make public the terrifying secret known only to a select few: Cylons now look like humans.