0 BCH

1 ACH (After Colonial Holocaust) denotes a period of 365 days, the epoch of which is the Fall of the Twelve Colonies. The events of this time period correspond to the majority of Season 1 and Season 2, in addition to:

Return of the Cylons

• Zero Hour:
  • The Cylon fleet gathers at a staging area close to The Colony ^{(TRS: "The Plan")}.
  • John Cavil makes his final preparations for the impending assault and visits a sealed-off resurrection chamber housing deactivated copies of the Final Five ^{(TRS: "The Plan")}.
  • The Armistice Station is destroyed by Cylon forces, appear, and show themselves, (albeit in a more advanced form, as well as a humanoid version) for the first time in 40 years ^{(TRS: "Miniseries, Night 1")}.
  • Laura Roslin is diagnosed with inoperable breast cancer ^{(TRS: "Miniseries, Night 1")}.
  • Galactica is decommissioned ^{(TRS: "The Plan" and "Miniseries, Night 1")}.
  • Pegasus undergoes refit while Kendra Shaw is assigned to the ship from the Ministry of Defense ^{(TRS: "Razor")}.
  • A Cavil meets with Caprica-Six, who gives him the access codes to the Colonial Defence Mainframe ^{(TRS: "The Plan" and "Miniseries, Night 1")}.
  • The Cylon strike force simultaneously jumps into orbit around all the Twelve Colonies and commences an all-out attack ^{(TRS: "The Plan")}, using strategic nuclear bombardment ^{(TRS: "Miniseries, Night 1")}.
  • Picon Fleet Headquarters is destroyed ^{(TRS: "Miniseries, Night 1")}.
  • Ellen Tigh is placed aboard Raptor from the medical ship Rising Star by John Cavil shortly before it escapes the destruction of Picon ^{(TRS: "The Plan", "Tigh Me Up, Tigh Me Down" and "No Exit")}.
  • Galactica's last Viper Mark VII squadron is destroyed ^{(TRS: "Miniseries, Night 1")}.
  • A battle near Virgon ends with the total loss of the remaining Colonial Fleet including the flagship Atlantia ^{(TRS: "Miniseries, Night 1")}.
  • The battlestar Pegasus luckily escapes the destruction of the Scorpion Fleet Shipyards ^{(TRS: "The Plan", "Razor" and "Pegasus")}.
  • The Cylons begin landing ground forces on the Colonies ^{(TRS: "The Plan" and "33")}.
  • Galactica engages Cylon Raiders and survives with moderate damage and 85 dead ^{(TRS: "Miniseries, Night 1")}.
  • Last transmission from the Colonies received by Laura Roslin aboard Colonial Heavy 798 from a fellow secretary ^{(TRS: "Miniseries, Night 1")}.
  • Case Orange contingency mechanism assigns Roslin the office of the President of the Twelve Colonies ^{(TRS: "Miniseries, Night 1")}.
  • Roslin gathers stranded civilian and military ships in the vicinity of Caprica ^{(TRS: "Miniseries, Night 1")}.
  • Commander Adama assumes overall Fleet command and orders regroup at Ragnar Anchorage ^{(TRS: "Miniseries, Night 1")}.
  • Roslin's fleet survives two Cylon attacks and meets at Ragnar ^{(TRS: "Miniseries, Night 2")}.
  • Galactica changes from battle stance to civilian protection, and escorts the civilian fleet from Ragnar towards the Prolmar Sector ^{(TRS: "Miniseries, Night 2")}.
  • The Twelve Colonies of Kobol lie in irradiated ruins. Their military has been utterly defeated and their infrastructure has been crushed. The result of the engagement is a complete victory for the Cylon forces ^{(TRS: "Miniseries, Night 2" and "The Plan")}.
  • The Cylon occupation of the Colonies begins ^{(TRS: "33", "Downloaded" and "The Plan")}.

Season 1

See Timeline - Season 1 (RDM)

Season 2

See Timeline - Season 2 (RDM)