Have you ever wondered how the Left 4 Dead series began? It started with a heist! A teaser trailer showcases a collaboration between Valve and developer Overkill. Titled No Mercy, the in-development content will allegedly tell the story of how Left 4 Dead's zombie outbreak began. From the looks of things, it involves a group of armed thieves who assault Mercy Hospital in search of a particular patient's blood. Naturally, the search is not a peaceful one. [media] http://www.youtube.com/watch?v=GMXkkSG3IN0 [/media]
