Battlestar Galactica is set in a distant part of the galaxy where a society of humans live on a series of planets known as the Twelve Colonies.

Historically, the Colonies have been at war with a cybernetic race known as the Cylons. When the Cylons ambush the Colonies, they destroy the planets and devastate their populations.

The remaining few human survivors flee into space on the Battlestar Galactica, which is the only ship that survived the attack.