Valve have announced a release date of October 5th for their Left 4 Dead and Left 4 Dead 2 DLC, The Sacrifice. The download will cost 500MSP on 360, and nothing on PC, and fills in the plot gap linking the survivors of the first game with the survivors of the second. Set before The Passing, the DLC also adds a new "Sacrificial" finale which'll see players choosing which of the original characters gets savagely torn to bits by the zombie horde. Cheerful stuff, then.
Owners of Left 4 Dead 2 will also be able to play through one of the original campaigns, No Mercy, using the new characters. Both campaigns will be playable in versus, survival, and scavenge modes.