The Cylons were created by man. They evolved. They rebelled.
Ater 4,571 days, the Cylon War ended with a sudden armistice. Peace lasted 40 years. But now the Cylons are back, as fierce and combative as ever. They want to exterminate what remains of Mankind. And they have a plan.
The Twelve Colonies are wasted and in ruins. But the Colonial Fleet is there, to face Cylon spaceships and protect what it is left of Mankind.