- Edward James Olmos as Commander William Adama
- Mary McDonnell as President Laura Roslin
- Katee Sackhoff as Lt. Kara 'Starbuck' Thrace
- Jamie Bamber as Cpt. Lee 'Apollo' Adama / Lee Adama / Major Lee 'Apollo' Adama
- James Callis
- Tricia Helfer as Number Six
- Grace Park as Lt. Sharon Valerii - Boomer
- Michael Hogan
- Aaron Douglas as Crew Chief Tyrol
- Tahmoh Penikett as Lt. Karl C. 'Helo' Agathon
- Michael Trucco as Samuel Anders / Ensign Samuel Anders
- Alessandro Juliani
- Kandyse McClure
- Nicki Clyne
The world ended with no warning, and all that was left ... was hope.
The Cylons were created by the people of the Twelve Colonies. Intelligent robots, they were used as slaves and soldiers to fight humanity's wars. But the Cylons became sentient and they rebelled. Man and machine fought to a bloody stalemate, then the Cylons withdrew to a remote region of space.
A truce between the Twelve Colonies and the Cylons lasted for 40 tense and silent years. Each year, on the anniversary of the treaty-signing, humanity sent an envoy to the neutral ground of Armistice Station to meet with a Cylon envoy. For 39 years, no Cylon envoy came.
Then, on the 40th anniversary, a stunning blonde - a Cylon in human form - met the human envoy ... moments before the Cylons vaporized the station and launched a genocidal attack on the Twelve Colonies.
In one devastating day, billions of human lives were consumed by nuclear fires. Only those souls fortunate enough to be aboard starships were able to band together and escape and flee into deep space, led by the sole surviving Colonial warship, the battlestar Galactica.
The Galactica and its crew seemed to be unlikely saviors for humanity's fewer than 50,000 desperate survivors. The ship was old and had been about to be decommissioned and turned into a museum when the Cylon attack occurred. In the aftermath its commanding officer, William Adama, found himself responsible for safeguarding the last remnants of the human race.
Meanwhile, the annihilation of the Colonial government on Caprica resulted in the succession of Laura Roslin, the Secretary of Education, to the presidency. Driven by prophetic visions and political necessity, she set the fleet upon a quest that will take it into the farthest reaches of unexplored space ... in search of the mythical, lost "13th colony" - Earth.