The Sacrifice is a three-map campaign with a story that links the two games and takes some of the mystery out of the events portrayed in Valve’s previous L4D2 DLC pack, The Passing.

“The Sacrifice” is the prequel to “The Passing,” and takes place from the Left 4D Survivors’ perspective as they make their way South. We know Bill dies in “The Passing” but how and why? You can read the comic to find out the official version of events or this October 5th you can play the game to choose your own ending.

The Sacrifice is available for L4D and L4D2, and as an added bonus, the new DLC will give L4D players the new machineguns and melee weapons released in The Passing. And L4D2 owners will receive one of the original game’s most popular campaigns, No Mercy.