The Sacrifice is a digital comic book created by Valve Corporation based on the Left 4 Dead video game, detailing the events of the main characters from it, namely Zoey, Louis, Francis, and Bill, after the chronological final campaign, Blood Harvest. It accompanies a campaign in both Left 4 Dead and Left 4 Dead 2 of the same name. It also serves as a prequel to the campaign from Left 4 Dead 2 called The Passing, which makes allusions to the events.