Battlestar Galactica - Season 3 Episode 7
A Measure of Salvation

Apollo formulates a plan that threatens the very existence of the Cylon culture. Adama and Roslin must decide whether to follow through on the plan to use a biological weapon against the Cylons. DAnna Biers (Number Three) believes Baltar knows who created the virus that infected and disabled the Cylon baseship. She is willing to take extreme measures to learn the truth.