Details surface about Left 4 Dead series' upcoming expansions

We never thought we'd have to slap a spoiler warning on a post about downloadable content for the Left 4 Dead franchise -- and yet, here we are. The latest episode of GameTrailers TV revealed an intriguing plot point about the pair of new chapters for the original game and sequel. We respect that some of you might want to remain in the dark about the DLC until you finally get your hands on it. For the rest of you, check out the details just past the jump.
In Left 4 Dead 2's "The Passing" scenario, it was assumed you'd encounter all four protagonists from the first game. Valve's Chet Faliszek revealed the tagline for this scenario is "Nobody Survives Forever" -- as you might expect from the title, one of the original quartet has sacrificed him or herself in the events preceding "The Passing," which will be the focus of the upcoming Left 4 Dead 1 campaign.

This sounds like it could lead to some pretty neat gameplay implications, though really, if we can make through a campaign and only lose one person, that's a pretty good day in our book.