Left 4 Dead "The Sacrifice" DLC Coming October 5

Last month, Valve announced "The Sacrifice" downloadable content, which would ambitiously be released for both Left 4 Dead and Left 4 Dead 2. Today, the company finally made the plans concrete, giving word that the packs will hit on October 5. They will be free on the PC/Mac versions of the game, and 560 Microsoft points ($7) on the Xbox 360. The DLC will be available for both games as separate packs, but 360 owners should just buy one or the other, since the move is meant to accommodate all players rather than provide separate content.
The pack stars heroes of the first game in a cross-over with those from the second game, and will explain the death of a character as established in The Passing. Players can also go off-script and sacrifice one of the other three characters instead. It will contain stages in Campaign, Versus, and Survival modes, plus it will add the No Mercy campaign from the first game into the second. For those seeking closure from the previous story arc.