The fleet has been jumping every 33 minutes for 5+ days to outrun the Cylons, with no sleep. When the Olympic Carrier reappears after going missing during a jump, Adama and Roslin are forced to destroy it -- 1,300 people aboard -- on the slim chance Cylons are using it as a tracker.

Sharon 'Boomer' Valerii, acting on Cylon programming she isn't conscious of, sabotages Galactica's water supply and destroys 60% of reserves. The crew scrambles to find a new water source; Boomer is horrified to realize she did it with no memory of doing so.

A freak accident kills 13 pilots and Adama orders Starbuck to train replacements. Flashbacks reveal she passed Adama's son Zak on his flight exam out of love for him, knowing he wasn't ready -- a decision that got him killed. She refuses to train the new pilots when she deems them unfit. Part 1 of 2.

A humanoid Cylon suicide-bombs a crowded corridor on Galactica. Adama and Roslin are forced to publicly disclose that Cylons can look and act exactly like humans, triggering widespread paranoia. An innocent crewman is scapegoated and imprisoned by a tribunal, illustrating how fear erodes justice.

A physical Number Six appears on Galactica claiming to be 'Shelley Godfrey' with evidence that Baltar sold out humanity's defense codes. Baltar scrambles to disprove the frames while hiding his real guilt. Six vanishes mysteriously, leaving Baltar exonerated but shaken -- and still hiding everything.

Galactica discovers Kobol, legendary home of humanity and the key to finding Earth. Roslin -- acting on prophecy -- secretly orders Starbuck to steal the captured Cylon Raider and return to Cylon-occupied Caprica to retrieve the Arrow of Apollo. Adama discovers the betrayal; Boomer's Cylon identity begins to crack open. Part 1 of 2.

Adama sends marines to arrest Roslin aboard Colonial One, fracturing the fleet's leadership. Starbuck reaches Caprica and retrieves the Arrow. Boomer, finally confronted with her Cylon nature, shoots Adama twice at point-blank range. The season ends with Adama near death, Roslin in custody, and the fleet in crisis.

Adama is in surgery after being shot by Boomer. An emergency jump separates Galactica from the rest of the fleet, leaving Tigh in command of a ship under pressure with Lee and Roslin locked in the brig.

A Cylon centurion boarding party works to reach Galactica's engines and destroy the fleet. Tigh reluctantly partners with the imprisoned Lee to coordinate the defense and stop them.

Tigh's poor leadership decisions push the fleet toward chaos as he imposes policies that backfire. On Kobol, the stranded crew discovers a Cylon artillery emplacement they must destroy before rescue can arrive.

Tigh declares martial law after a confrontation with a civilian ship turns deadly, driving parts of the fleet toward Roslin's leadership. On Caprica, Starbuck and Helo link up with a group of surviving humans led by Anders.

Starbuck wakes in a Cylon-run hospital on Caprica and discovers the Cylons are harvesting human women as breeding vessels. She escapes, and Roslin makes a public appeal to the fleet to follow her to Kobol in search of Earth.

Starbuck returns from Caprica with the Arrow of Apollo and Sharon in tow, but Boomer's presence causes friction. Adama refuses to reunite with Roslin's faction while Lee aligns with her on the surface of Kobol.

Adama comes to Kobol and reconciles with Roslin. The group enters the Tomb of Athena and experiences a vision that points the way toward Earth using the twelve constellations -- confirming Earth is real and giving them a navigational clue.

The fleet encounters the Battlestar Pegasus, which survived the Cylon attack under Admiral Cain's brutal command. The reunion quickly sours as Cain outranks Adama, the Pegasus crew's war crimes surface, and Baltar discovers a familiar Cylon prisoner aboard -- a Six who has been tortured.

Starbuck returns with recon footage of a Cylon Resurrection Ship -- the vessel that allows dead Cylons to be reborn. Roslin brokers a fragile truce between Adama and Cain while both secretly order the other's assassination. A joint strike on the Resurrection Ship is planned.

The combined fleet destroys the Resurrection Ship, removing Cylon immortality as a local threat. Adama and Cain's mutual assassination orders hang in the air until events resolve them another way; Apollo survives a life-or-death moment that haunts him; and Baltar moves pieces that will have long consequences.

A terminal Roslin, in flashback-driven final hours, orders Sharon's Cylon-hybrid baby terminated, believing it dangerous. Baltar synthesizes a cure using fetal blood that saves Roslin's life. A pro-Cylon peace group begins operating inside the fleet.

Two Pegasus Raptors disappear on a suspicious rescue mission, and the incompetent new Pegasus commander makes things worse before Lee takes charge. Roslin rules against a refugee's right to abortion, hardening her image as president -- and Baltar pivots this into a campaign issue.

On Cylon-occupied Caprica, a newly resurrected Boomer (Caprica-Sharon) struggles with her identity while Number Six tries to radicalize her. The two begin to question Cylon doctrine from within. Simultaneously, Sharon's hybrid baby is born on Galactica and immediately handed to Baltar, setting up the endgame of the season.

Starbuck leads a mission back to Caprica to rescue Anders. Tyrol's recurring nightmares hint at something deeper. Most critically: a habitable planet is discovered during the election campaign, forcing Roslin and Baltar to stake out opposite positions on whether the fleet should settle or keep searching for Earth.

Baltar wins the election; Roslin nearly steals it but stands down. The fleet settles New Caprica. Then the episode jumps one year forward: the fleet is complacent, Baltar is a figurehead, and the Cylons find them -- and occupy the planet. The season ends with the fleet having surrendered.

Four months after the Cylons took New Caprica, Tigh and Tyrol lead a suicide-bombing resistance while Starbuck is kept prisoner by Leoben. Adama debates whether Galactica can risk a rescue mission.

Cylon reprisals escalate after suicide bombings; Roslin is arrested and Baltar pressures her to cooperate. Ellen Tigh secretly gives the Cylons the resistance commanders' meeting location to save Saul.

Tyrol races to save Cally from a Cylon execution list while Sharon leads a ground team ambushed by Cylons -- revealing a mole inside the resistance. D'Anna begins dreaming of the Final Five.

Galactica executes a suicidal atmospheric jump to cover the New Caprica evacuation against four Basestars; Pegasus sacrifices herself. Tigh kills Ellen for her betrayal. The fleet escapes -- but Baltar stays with the Cylons.

A secret tribunal led by Tigh and Tyrol airlocks suspected collaborators without trial; Roslin shuts it down by granting a blanket amnesty. Baltar is put on trial by the Cylons and acquitted.

Baltar living among the Cylons wonders if he is one; the Cylons dispatch a Basestar toward Earth using his star map and it arrives to find a virus wiping out the crew. Gaeta independently begins cracking Baltar's map aboard Galactica.

The fleet captures infected Cylons and Lee proposes using them as a biological weapon to wipe out the entire Cylon race via resurrection networks; Helo quietly sabotages the plan. D'Anna tortures Baltar for answers about the virus.

The fleet stops at an algae planet where Tyrol discovers a temple possibly pointing to Earth; Cylons arrive and a standoff begins with both sides threatening mutually assured destruction. Hera is revealed to still be alive aboard a Cylon ship.

The algae-planet standoff resolves; D'Anna triggers the temple's supernova vision, sees the faces of the Final Five, and is boxed (permanently deactivated) by Cavil for the forbidden knowledge. Baltar is captured by Galactica. Hera is recovered.

Adama and Roslin drug-interrogate Baltar aboard Galactica; he reveals little of use but survives. Lee is forced to choose between Dee and Kara, and chooses to stay in his marriage.

Kara, increasingly consumed by visions, flies into a storm on a gas giant and her Viper explodes with no wreckage found. Lee watches her die. Her fate and the meaning of her visions will not be resolved until Season 4.

Baltar's new defense attorney, the eccentric Romo Lampkin, survives an assassination attempt; Lee is pulled onto the defense team. The fleet grieves Starbuck but the narrative momentum shifts fully to the coming trial.

Baltar's trial proceeds with damaging testimony; Roslin's cancer returns and her use of chamalla creates a credibility problem. Tigh, Tyrol, Anders, and Tory separately begin hearing a strange music no one else can hear.

Lee's courtroom monologue sways the jury and Baltar is acquitted. Guided by the mysterious music, Tigh, Tyrol, Anders, and Tory realize they are four of the Final Five Cylons. Starbuck reappears alive in a brand-new Viper, claiming she has been to Earth.

Starbuck reappears in a pristine Viper claiming she's been to Earth, while Roslin suspects she's a Cylon. The four newly revealed Final Five members (Tigh, Tyrol, Anders, Tory) struggle in silence with the knowledge of what they are.

Roslin confronts Starbuck at gunpoint, convinced she's a threat. Aboard a Cylon Basestar, the Number Sixes and Eights vote to unbox D'Anna over the Ones' objection, fracturing Cylon unity. Lee Adama departs Galactica to take his father's Quorum seat.

Cally overhears Tyrol, Tigh, and Tory discussing their Cylon nature; before she can act, Tory spaces her to protect the secret. The Cylon civil war escalates with the Cavil faction boxing the rebel Threes.

After a near-mutiny on the Demetrius, Starbuck leads her crew to the rebel Basestar to begin the alliance against Cavil. Roslin, undergoing cancer treatment, bonds with one of Baltar's followers and begins to understand his appeal. Sets up the Hub mission.

The fleet and rebel Cylons finalize a plan to destroy the Resurrection Hub, which would make all Cylons permanently mortal. Athena kills Natalie after the Six becomes unnervingly close to Hera, setting off the Opera House arc. High-stakes setup for the Hub.

D'Anna reveals she knows the Final Five are in the fleet and holds the fleet hostage. The three remaining Final Four members are outed to Adama when Kara's Viper signal triggers the Cylon music in them. The fleet jumps to Earth -- and finds a nuked wasteland. Devastating cliffhanger.

The fleet discovers Earth was destroyed 2,000 years ago by nuclear war, and the skeletons in the ruins are Cylon -- the 13th Tribe was entirely Cylons. Tigh, Tyrol, Anders, and Tory each recover memories of dying on that Earth. Starbuck finds her own corpse. Harrowing, slow-burn gut punch.

Gaeta orchestrates a fleet-wide mutiny with Zarek, freeing him and seizing control of Galactica deck by deck. Adama and Tigh are captured; Roslin barely escapes to the Basestar. One of the best-paced episodes in the series.

Adama escapes custody with help from Baltar's cult and reclaims the ship. Zarek has the entire Quorum executed. When the mutiny collapses, Gaeta and Zarek are tried and shot by firing squad. Uncompromising and earned.

Anders, shot in the head, begins recovering long-buried memories of being one of the original Earth Cylons who travelled to the Colonies after Earth's destruction. Meanwhile, Ellen -- resurrected after Saul poisoned her -- remembers the full history of the Final Five and their deal with Cavil. Crucial lore dump, excellently delivered.

Adama calls for volunteers for a one-way assault on the Cylon Colony to rescue Hera. Intercut throughout are pre-Cylon-attack flashbacks showing Baltar's farm life, Roslin learning of her family's deaths, and Lee and Kara meeting for the first time. The flashbacks divide viewers but land emotionally by the finale.

Galactica crashes into the Cylon Colony in a desperate rescue of Hera; the Opera House vision is finally resolved as Baltar and Six lead Hera to the CIC. Starbuck jumps the fleet to a new habitable Earth. The survivors settle there as primitive hunter-gatherers, abandoning technology -- Starbuck disappears, and a 150,000-year epilogue reveals this is our Earth. Visually and emotionally powerful; the ending's anti-tech thesis and Starbuck's unresolved nature remain genuinely controversial.