The Twelve Colonies of Man are annihilated by the Cylons. Adama, commanding the last surviving Battlestar, takes it upon himself to lead all remaining survivors aboard 220 ships to find a new home. After the Galactica's fighter pilots successfully navigate a path through the Nova of Madagon minefield, the spoiled Sire Uri proposes to settle down on Carillon, where food and entertainment are provided by the natives. However, Adama suspects a Cylon trap.
- Across the galaxies exist The Twelve Colonies Of Man, worlds settled millenia ago by refugees from mankind's motherworld, Kobol. It is the seventh millenium of recorded time, and the Twelve Worlds are an advanced and proud nation. Flying through space are the capital warships of the Colonies - battlestars. Each of these flying fortresses is a long and lean starship sporting an enormous forward station, long flight bays to both sides of a comparatively slender midship section sporting a mammoth personnel bay on the underside, and mammoth nuclear-based engines capable of projecting each ship across the stars. Each battlestar is mammothly armored and heavily armed with antiassault laser batteries, powerful laser-pulse cannons for ship-to-ship combat, and hypervelocity missile dischargers. Each battlestar also sports over 200 fighter craft, slender tri-engined machines known as Vipers.
But the main contingent of battlestars is not engaged in combat operations - this group is voyaging to the planet Cimtar for a ceremony at which a treaty of peace will be signed with the Cylon, a race of alien cyborgs created from a race of fully-evolved saurian beings; their leader, Sobekkta, had led the Cylon race to conquer star system after star system until allowing the Cylon race's own cybernetic technology to subsume their very essense, thus replacing their biological bodies with cybernetic armor and technology, and exterminating whatever biological Cylons survived.
The Cylon Empire - sometimes referred to as an Alliance, a euphemism for the subsummation of captured biological races into the Empire's cybernaut technology - has been at war with the Colonies for one thousand years after they had conquered the world of Hasari and were driven back by intervening humans; the Cylons responded by exterminating the Hasari world and launching war into the Colonies, and the Supreme Cylon, Sobekkta, bears an especially virulent hatred of humans. Now, however, the Cylons have accepted peace, and a toast in honor of this peace is held on the flagship of the Colonial Fleet, the Atlantia, by the Twelve Worlds' ruling Council, led by President Adar.
Adar is especially close to Baltar, a human arms and Tylium fuel dealer who has earned for himself command of a battlestar and was liason between the Cylons and the Colonies for peace negotiations. One other member of the Council, however, is less than enthusiastic - Adama, the commander of the Fleet's mightiest battlestar, the Galactica. Adama has studied the Cylon Empire as thoroughly as possible and understands the hate that drives their very essense and the incompatability of humanity, with its love of freedom and independence and resistance to oppression, with the Cylon cybernauts.
Two of Adama's children - Apollo, commander of the Galactica's fighter contingent, and young Zaccariah - are assigned to fly ahead of the Fleet on patrol of the Cimtar area. When they approach the area they encounter a spatial cloud surrounding the moon, and two star craft are scanned within the cloud. Apollo penetrates into the cloud and finds a pair of Cylon tankers - both empty. When the scanners of their Vipers become jammed, Apollo becomes suspicious, and penetrates further into the cloud.
What he finds is horrifying, for massing together is the largest armada of Cylon starfighter craft, known as Raiders, in the history of galactic warfare. Apollo and Zac are forced to flee, but they are pursued by four Cylon Raiders, their saucer shape a striking contrast to the slender needle-nose shape of the two Vipers. The Cylons open fire, but Apollo and Zac hit Inverse Mode thrusters, in effect stopping dead in space. The surprised Cylons overshoot them and become the pursued. Apollo and Zac thus turn the tables, opening fire and hammering three Raiders to destruction before the fourth outflanks Zac and lands a deadly laser burst that shatters his apex engine; Apollo dispatches the last Cylon, but emerging from the Cimtar area is the full armada. Unable to keep up with Apollo, Zac urges him to get to safety and warn the Fleet, and Apollo reluctantly hits full power and jumps back to the Fleet.
Adama and his second-in-command, Colonel Tigh, get word of the battle but Adama's request to launch additional fighters is rejected by Adar on the advice of Baltar, fearful that a display of fighters will antagonize the Cylons before the scheduled rendezvous. Adama does, however, call a battle stations drill for the Galactica, which rudely interrupts a successful card game mastered by Lieutenant Starbuck, the Fleet's best pilot and most notorious rogue.
It is not until the Cylon star legion enters close scanner range - with Zac barely keeping ahead of them - that Adar realizes there is something wrong, by which time Baltar has curiously disappeared. Zac pleas over his communications for help, but the Cylons fire a fatal charge that pierces Zac's cockpit and obliterates his Viper - and witnessing this tragedy on scanner are Adama and his daughter, scan coordinator Lieutenant Athena, who breaks down at the sight of her brother's death.
The Cylons now open full fire on the surprised battlestars and Adama launches his Vipers under attack. The other battlestars of the Fleet try to launch their Vipers, but many are slaughtered upon launch and the Cylons have near-free reign with which to strafe the besieged Fleet. The Galactica's badly outnumbered pilots and her onboard antiassault operators fight without letup as laser fire slaughters Cylon ship after Cylon ship. Among the Galactica's pilots are Lieutenant Boomer, a level-headed engineer, and Jolly, a heavyset wingmate. They nonetheless take fearful casualties - one of which is a pilot who warns Starbuck about how dangerous it is out here scant seconds before Cylon fire blasts his ship out of the universe.
Apollo proceeds to the Galactica's bridge and learns of Zac's death. When he tells Adama and TIgh about the two tankers, Adama realizes that a second Cylon fleet is en route to the now-underprotected Colonies, whose own defenses are in stand-down due to the peace treaty. Adama requests permission to sortie the Galactica to the homeworlds, but must bear tragic witness as a Cylon phalanx blasts away at the Atlantia before the ship's reactors detonate and the battlestar explodes, a blast of fire and debris that shocks and demoralizes all who witness.
Adama now orders the Galactica to break off and return to the Colonies. Long range scans pick up a television newscast about a celebration in the capital city of Caprica hosted by Serina, a beautiful woman who is the planet's most famous broadcast journalist. Above the planet, however, orbit Cylon base stars, twin-tiered saucer-shaped fortresses under the personal command of the Cylon Imperious Leader, who bears the reptilian husk of Sobekkta and commands from a dark cylindrical chamber atop a high throne. When he gives the order to attack, Cylon Raiders emerge from their base stars and bear down upon the helpless planets. Serina's broadcast captures the first wave of Cylon Raiders as they open fire on Caprica's capital city. The Cylons strafe the city and blast buildings, and planetwide the Cylons lay down destruction witnessed on scanners by the Galactica, helpless to assist the besieged planets.
The Cylons, however, make the mistake of moving on to regroup, giving Adama a chance to fly down to Caprica with Apollo and retrieve some belongings from his shattered home - and to mourn the death of his wife Ila. Crowds of refugees see Apollo and angrilly demand answers, but are moved to silence when they learn the totality of the Colonies' defeat. They are further moved by the presence of Adama, who tells the people they must assemble in every assorted star vehicle that will carry them.
Thus, with the Cylons regrouping well away from the Colonies, vast numbers of ships fly into space bearing survivors for a rendezvous with the Galactica. Days later Baltar surveys the wreckage of Caprica with approval, as a pair of Cylon centurions informs him of the flight of survivors. Baltar scoffs at the notion that they could possibly go far and tells his centurions to carry out their standing order of exterminating the human race.
The survivors have now rendezvoused with the Galactica and Adama tells representatives of each ship that they cannot stay in this galaxy - they must undertake a journey discussed in The Book Of The Word (the Bible of the Colonies) to a mythical thirteenth colony many galaxies distant, the last known remaining outpost of human civilization. It is a planet known only as Earth.
The prospect of such a journey, with no end seemingly conceivable, has an effect on Athena, who is in love with Starbuck. Starbuck, however, does not believe anyone will survive to see another homeworld, and he and Athena put up a brave front as they feel they must break off any relationship they have had.
First, though, the Fleet must find sources of food, water, and Tylium rock for use in the nuclear engines of the ships, and this coming after Apollo, checking on shortages among the Fleet, finds Sire Uri, a member of the Colonies' new government, engaged in massive hording. Adama proposes to the recently-formed new Council Of Twelve that the Fleet warp to the planet Carillon, a distant world explored for fuel years earlier but rejected as a source. The Council initially rejects this notion but Captain Apollo offers a scheme to deploy the Fleet through a starfield, the Nova of Madigon, that leads directly to Carillon - a starfield studded with Cylon mines. Apollo proposes "finding one or two volunteers" (Starbuck and Boomer) to join him by flying Vipers shielded from the starfield's blinding light and enormous heat and firing laser cannons to sweep up Cylon mines. Adama objects but is overruled by the Council led by - of all people - Sire Uri. He and Apollo engage in a bitter argument over the mission and over Sire Uri, and Apollo must tell his father that the Fleet doesn't need their leaders to be nursing wounds while fire still rages.
The night before the mission, Starbuck chats with a young woman named Cassiopeia. Cassiopeia is a socialator from Gemon; socialator is a position of glorified female escort, and Starbuck, a notorious womanizer, is naturally attracted. In the dark launch bay of the Galactica Cassiopeia (who is also a trained medical technician destined to join the battlestar's medical corps) seduces Starbuck, and leads him into one of the ship's launching apertures. Before they can go far, however, they are scanned by Athena and she activates the tube's Steam Purge, giving both lovers a hot foot.
Starbuck shakes off this embarrassing episode and with Boomer and Apollo leads the sweep of the Madigon Nova, and the Fleet arrives in the Carillon system. Landing operations begin searching for Tylium, and Apollo leads one such mission with a pair of new friends - Serina, and her son Boxey, who has been provided a robotoid "daggit" (an alien dog) named Muffit. Apollo has found in Serina a compatriot who helps him cope with the death of Zac, and the two begin falling in love.
Starbuck and Boomer lead another exploration, and come upon a strange source of light; they are further shocked when emerging from the light is a woman, a woman from the Tauron colony who not only knows nothing about the Final Destruction of the Colonies but hasn't a care in the universe but does have huge winnings of cubits (gold coins) from gambling casinos on the planet and is due for a star cruise later that night.
Entering the aperture from which the light eminates, Starbuck and Boomer come upon a paradisial underground world, a vast collection of entertainment venues, gambling venues, and eateries, all packed with humans from the Colonies, humans who have been here for months, even years. The two warriors discreetly explore the enormous chancery looking for the area's leader, and Starbuck even takes in a few gambling exchanges that net him a big pile of cubits, and is swayed by the singing of a trio of alien divas whose enormous heads combine two mouths with four eyes and a mixture of male and female voices.
Elsewhere Apollo comes upon a hot reading of Tylium, but the party is surrounded by a horde of insectizoid aliens, known as Ovions. They take the humans to their queen, Lotay, who informs them that others from their group have been found. Apollo and Serina are thus introduced to the gigantic underground chancery and reunited with Starbuck and Boomer.
Carillon contains the biggest Tylium mines in the galaxy, enough to supply the Fleet for many years. The Ovions offer the Fleet Tylium and also allows civilians to shuttle down to the planet to partake in its casinos and eateries. Adama and Tigh are concerned, especially as Sire Uri is leading parties of humans down to Carillon and has issued visitation permits to half the population. In his moments alone in his quarters, Adama narrates into a computerized journal expressing his thoughts and concerns about how Carillon seems too good to be true - which is indeed the case as several people take elevators to hotel rooms but wind up in the deep bowels of the planet and are seized by Ovions and paralyzed for use as food for Ovion hatchlings.
Adama's suspicions grow when he reexamines Fleet Operations intelligence on Carillon and finds that the traitor Baltar was the one who led the original expedition and declared Tylium was insufficient for mining. When a special session of the Council is called, Adama is aghast when Sire Uri proposes disarmament and negotiating a truce with the Cylons and thus settling on Carillon, in the delusional belief the Cylons will now leave the humans alone.
Adama is thus forced to undertake a risky end-around - in a secret meeting aboard Vipers in the Galactica's flight bay, Adama expresses concern to Tigh that the Cylons are massing for a strike on the Fleet while the people are busying themselves with the pleasures of the planet; Adama will surreptitiously deploy the Galactica's fighter phalanx to the planet surface well away from the mammoth chanceries, while Tigh is to seize all warrior uniforms possible and recruit anyone he can find to make them wear these uniforms and attend a planet-wide celebration mastered by Sire Uri, at which he'll propose disarmament and calling off conflict with the Cylons. Tigh proceeds to seizing uniforms, and when surprised by Starbuck and Boomer he must flex his officer muscle and chew out the two warriors because he's finding uniforms in "this condition!"
Having thus gotten out of that jam, Tigh fulfills his part of the mission, and when Apollo and Serina fly down to the planet they are fully in love, but trouble begins when Starbuck notices a member of his squadron, except the uniform is right but the man wearing it isn't. The man disappears in Carillon's elevators, and Apollo and Starbuck search for him. When they find the elevators won't go all the way down to their basement, they blast one of the controls and jerry-rig the linkages to deep within the planet surface.
It is here that they spot Queen Lotay in the company of several Cylon centurions. Instantly realizing the Carillon party is a trap, the two warriors hushedly debate what to do next, as they can't afford to leave the Tylium mines operational for the Cylons yet the Fleet's population is on the surface and since the planet is almost entirely composed of Tylium, ignition with a single laser shot will cause a fire that will spread until the entire planet is blown apart.
Their argument is stopped when Boxey, who is searching for his wayward daggit, suddenly appears and a centurion unsheaths a sword to behead the boy. Apollo opens fire and a running gun battle ensues, during which Apollo and Starbuck discover the Ovion hatcheries - and that Cassiopeia has been captured for food. They rescue Cassi and must stay a few steps ahead of a horde of centurions, all the while their laser fire igniting Tylium stores that will swell into mammoth explosions.
The entire Cylon garrison is activated and attacks the population in the chanceries, but warriors operating landrams - tracked vehicles with large laser turrets - arrive to provide devastating cover fire to evacuate the population. It is here that they learn that a Cylon base star, commanded by Imperious Leader himself, has launched its phalanx to attack the Galactica. The battlestar's warriors arrive at their launch fields, man their Vipers, and catapult into space and ambush the attacking Cylon phalanx.
While the Cylons scatter in retreat, Apollo and Starbuck dive into Carillon's atmosphere and skim its surface, below Cylon scanners, approaching the base star in an attack formation. Their comm chatter intends to give the impression to the Cylons that an entire phalanx of vipers, rather than just the two of them, is on attack course toward the base star. A centurion advises the base star commander that they are under attack by a large number of vipers, while their own fighters have been decimated. The Imperious Leader, beginning to panic, orders the base star into the gravity of Carillon to evade the attack just as the planet reaches vapor point and explodes, taking the base star with it.
The Fleet is now safe to proceed on its journey to find the planet Earth, but the Cylons are not finished at all. A new Imperious Leader is activated and dragged into his chamber at his request is Baltar, the human traitor. Baltar had been condemned by the previous Supreme Cylon to public execution, but the new Cylon ruler wishes to give Baltar command of Cylon forces, to set a human to catch humans. Baltar is thus spared, but first he must be teamed with a Cylon second-in-command, a Cylon sentient who goes by the name of Lucifer.....