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.

Tigh has to work with Lee to defeat a Cylon boarding party that threatens to take over Galactica and destroy the fleet.

Tigh imposes martial law and threatens to split the fleet as Lee works to free President Roslin and organize democratic resistance.

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

President Roslin's fragile coalition is put to the test in the first part of a two-part story. Apollo, who has sided with Roslin, runs into a conflict with Zarek and his accomplice Meier.

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.

A reporter is sent to Galactica to chronicle the harsh realities of life during wartime.

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?

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

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.

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.

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.

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.

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."

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.

Apollo assists in the search for a missing Raptor team as the new commander of the Pegasus grows increasingly unstable.

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.

Chief Tyrol is plagued by terrifying dreams and seeks the aid of a priest. Kara leads a rescue mission to Caprica. Roslin and Baltar go head-to-head in a presidential debate that changes dramatically with the discovery of a habitable planet.

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