The Battlestar Galactica two-hour series finale aired on the Sci-Fi Channel on Friday, March 20, 2009. During the second half of season three, writers Ronald D Moore and David Eick announced that season four would be the final season in the series.

• This page contains spoilers for the ending of the series Battlestar Galactica.

• Warning: This section contains spoilers for the ending of Battlestar Galactica!

The series finale tied up several series storylines. The final war between humanity and cylons ends in a brief truce. The Cylons agree to stop fighting and handover the cylon/human hybrid Hera for exchange of the resurrection ship plans. The plans are held collectively by the final five. During a download of the plans to the cylons, Gaylon Tyrol kills Tory Foster when he learns through the download process that she murdered his wife Cally. The download interruption causes a "Mexican standoff" between the cylons and humans. In the chaos, Cavill kills himself and nuclear missles are fired at Galactica. In order to escape, Starbuck uses the music notes she received from Hera earlier in the season to "jump" Galactica to mysterious coordinates. The coordinates put them in proximity to a habitable Earth. The Earth of our past. The rest of the fleet follows Galactica to their new home.Chicagotribune.com: Battlestar Galactica's series finale, Daybreak (March 21, 2009)

The vision or "head" characters of Six and Baltar are revealed to be divine guides or antagonizers. Their purpose was to inspire the pivotal characters of Baltar and Six in a direction of action during a crisis. Kara "Starbuck" Thrace is revealed to be something which may be similar to the "Head Baltar" or "Head Six", possibly divine but different then anything we've ever seen on the show. During a conversation with Lee Adama, Starbuck mysteriously vanishes into thin air. Only the memories of Starbuck are left as comfort. The centurion cylons which were under Cavil's control are freed to live on their own. The fleet's ships and the advanced technology of Caprica are all destroyed by having Sam Anders, in a suicide mission, purposely guide and crash the crafts into the sun. The plan is to start anew without the technology which caused so much grief and problems for the citizens of Caprica.Chicagotribune.com: Battlestar Galactica's series finale, Daybreak (March 21, 2009)

President Laura Roslin finally dies from her illness. Admiral William Adama stays by her side. The rest of the characters settle and scatter on Earth. It is revealed that the Earth we, the viewers, now live in was a result of the genetic mixing of Cylons, humans from Caprica and indigenous people already present on the planet. The series flash forwards 150,000 years to today's society, with the ironic foreshadowing of humanity's experimentation with robots. The overall tone of the show's ending however is of hope, which creator Ron Moore purposely wanted to do since the show is notorious for its pessimism.Discover: Still got questions? We've got answers!

Battlestar Galactica begins with the story of the first human and cylon war. The war has been over for forty years when the series begins, but every year the humans send a representative to the armistice with a treaty for the cylons to sign. The cylons ever appear, until two arrive escorting a beautiful blond woman who approaches the representative and asks him if he's alive. She tells him to prove it, and then kisses him as the ship begins to blow up around them.

Introduction to the crew of a war battlestar in preparation of retiring (the Galactica,) begins with Admiral William Adama and follows a group touring the Galactica in preparation for her retirement; the ship is becoming a museum. A number of the characters introduced are attending the retirement ceremony on Galactica, including Secretary of Education, Laura Roslin, and Captain Lee "Apollo" Adama. Two other major characters, the ship's Executive Officer, Saul Tigh and rogue viper pilot Kara "Starbuck" Thrace are shown fighting at a card game. On Caprica the character Gaius Baltar, who is a well-known scientist, discovers that his sexual escapades with a humanoid cylon model helped bring about the destruction of the Twelve Colonies. This humanoid cylon, later known as Caprica Six, sacrifices herself to save Baltar, and eventually he earns himself a place on the Galactica.

Throughout the series, the surviving members of humanity spend their endless days on the run from the cylons, while simultaneously searching for a new home for humanity. The show has often drawn from actual news and politics, reflecting them within the series as well to create a hook viewers could identify with.Sci-Fi: About Battlestar Galactica

With the Galactica falling to pieces, Adama and what's left of the fleet divide themselves in two, one half on a suicide mission to save the firstborn human-cylon hybrid child from the hands of an evil cylon intent on tearing the little girl apart to discover the secrets of immortality. The second half of the fleet will go on in search of a home for humanity. Adama and his men will take the Galactica on her last mission, sacrificing themselves to save the future of human and cylonkind.