While Commander Adama leads the rag-tag fleet of ships to the planet Kobol, where he hopes to find clues of Earth's location, the Viper pilots contract a disease, making it necessary for the women to take on fighter patrol duties. But the traitor Baltar leads the Cylons in an attack on the Galactica.
The Cylon Empire tricks the Twelve Colonies into believing they are striving for peace. Then they ambush the unprepared colonies and destroy the military's Battlestar fleet. One surviving Battlestar, the Galactica, under the command of Commander Adama, gathers the remaining humans and leads them in the search for the legendary 13th colony called Earth.