In the seventh millennium, a fleet of space battlestars from the twelve colonies of mankind travels to a peace conference that will bring an end to the thousand-year war with the robotic Cylon race. Aboard the Battlestar Atlantia, President Adar, leader of the Council of Twelve, thanks Count Baltar for making the armistice possible, but Commander Adama of the Battlestar Galactica remains wary of the Cylons, who have always loathed mankind. Meanwhile on Galactica, Captain Apollo, a top colonial warrior and eldest son of Adama, allows his eager younger brother, Lieutenant Zac, to accompany him on a routine reconnaissance patrol. However, during the mission, Apollo and Zac are ambushed by hostile fire. Apollo returns to the Galactica to warn the fleet, but Zac’s starfighter loses an engine and trails behind. When Adama learns of the attack, he asks permission to launch interceptor fighters as a precaution, but on the advice of Baltar, Adar insists on restraint for the sake of the peace mission. As an alternative, Adama places warrior starfighters on alert. When thousands of Cylon spacecraft close in on the colonies’ fleet, Galactica is the only battlestar able to react in time. Atlantia is obliterated. In his final moments, Adar realizes that the peace conference was a trap. After returning safely, Apollo is distraught to hear that his brother was killed while approaching the docking bay. Realizing the magnitude of the Cylon’s ambush, Adama watches the simultaneous bombing of the unprotected colonial planets. In the midst of the battle, Adama and Apollo journey to their home planet Caprica. There, Adama finds his house in ashes. As he mourns the loss of his wife Ila, a group of survivors approach and demand to know what happened to the planet’s defenses. Apollo informs them that Galactica is the only remaining vessel of the colonial fleet. In the hope of maintaining the existence of the human race, Adama sends a message throughout the twelve colonies that survivors should escape in any spacecraft that will carry them. In the exodus, 220 assorted vessels set forth and rendezvous with Galactica. Meanwhile, the traitor Baltar reports to the Cylons that the destruction of mankind and the colonies is complete, but the Cylons are not as confident based on information about survivors. On Galactica, Adama holds a meeting to announce that their new mission will be to seek out a legendary sister world, known only through ancient writings. Existing in another star system, this possible thirteenth colony of mankind is called Earth. During the journey, Apollo and his fellow warriors, Lieutenants Starbuck and Boomer, survey damage and supplies among the motley fleet of ships. On the freighter Gemini, passengers are in desperate need of food and water, and Apollo learns that the rations were contaminated by pluton poisoning from the Cylon bombs. At the freighter’s elite club level, he confiscates abundant provisions from the wealthy Sire Uri and distributes the hoard to the starving passengers. While conducting the survey, Apollo befriends an attractive woman, Serina, and her son, Boxey, who is distraught after losing his daggit, a canine-like pet, during the bombing. Back on Galactica, there are no signs of Cylon pursuit, and the new Council of Twelve debates where to land for provisions. Adama suggests the planet Carillon, inhabited by the Ovions, but his nemesis Sire Uri opposes the idea because Carillon is too far. As a solution, Apollo makes an audacious proposition that they can attempt a direct route to Carillon if starfighters sweep the minefields through the straits of Madagon, ahead of the fleet. The Council agrees and Apollo, Boomer and Starbuck clear a path. Meanwhile, Baltar is brought before the Cylon leader and beheaded for misguiding the Cylons about the complete destruction of mankind. On Carillon, search teams use landrams or ground expedition tanks, to explore the planet’s surface. During their exploration, Boomer and Starbuck encounter a luxurious gambling resort, full of vacationers who are oblivious to the destruction of the colonies. The casino, run by the insect-like Ovions, fascinates Starbuck because no one seems to lose money. While searching for tylium deposits to extract fuel, Apollo and Lieutenant Jolly are guided by Ovions to the gambling palace with its temptations of food and drink. Later as survivors disembark for the luxuries of Carillon, Sire Uri reports that the Ovions have extended every courtesy, but Adama is suspicious of this strange oasis for intergalactic travelers at the edge of the star system. At a special Council meeting, Sire Uri proposes that the colonies ask for mercy from the Cylons and lay down their weapons as a sign of commitment. Adama immediately denounces the idea. When Adama walks out, Sire Uri suggests a celebration on the resort in honor of the three heroic warriors who cleared the path to Carillon as an ideal forum to sway the military toward disarmament. In secret, Adama meets with his loyal second-in-command, Colonel Tigh. Sensing that Carillon is a trap, Adama thinks Sire Uri’s military tribute is the ideal time for the Cylons to launch another sneak attack, when troops will be away from the fleet at a party. Since the Council has ordered all warriors to attend the ceremony, Adama asks Tigh to dress civilians in military uniforms for the event, while a reserve of real warriors will be in position to fight. Adama even keeps his son Apollo unaware of the scheme, but as the tribute begins Apollo notices warrior imposters in the crowd. To investigate, Starbuck and Apollo follow three imposters to a restricted lower level. There, they happen upon Cylons conspiring with the Ovions and attack them with their laser guns. As their weapons trigger fires throughout the underground tylium maze, the two warriors realize that the combustion will transform the planet’s bedrock of fuel into a gigantic bomb. When they turn a corner, Apollo and Starbuck discover casino patrons stuffed in the cells of a giant hive, as nourishment for the Ovion young. They surmise that the Ovions are providing tylium fuel to the Cylons, and in exchange, the Cylons are facilitating the Ovion need for human bodies. Upstairs at the ceremony, Apollo orders everyone to leave. As their fellow warriors are prepared for battle with landrams and starfighters nearby, Starbuck and Apollo realize Adama’s clever scheme. The Cylons assume that they are launching a sneak attack, but a squadron of Galactica pilots surprises them and overpowers their fighter craft. In a daring move, Starbuck and Apollo pursue the undefended Cylon base station, forcing it to retreat closer to Carillon. To escape radar detection, the base station hovers above the surface. When the smoldering planet explodes, the blast destroys the Cylon command. Apollo and Starbuck return to Battlestar Galactica, a temporary home until they find Earth.