'One 4 Nine' is a four-level campaign for Valve Software's Left 4 Dead 1. The setting is the Nevada Desert. The U.S. Army have built a Military base around an ancient 'alien tomb', and after years of trying have finally managed to open it. The four survivors - Francis, Bill, Zoey and Louis - have heard rumors of a fortified safe zone located in the U.S Army's base, but have no knowledge of the tomb, nor what will await them upon arrival...
One 4 Nine is featured by Valve on l4d.com from today for the next few weeks.
I'm nearing completion of the L4D1 version of the campaign (I'll convert it to L4D2 when I'm happy with the L4D1 version).