If you are looking for the narrative plot of the game itself, Left 4 Dead 2 follows four survivors— Coach, Ellis, Nick, and Rochelle
If the custom map doesn't show up in your map list, ensure it's correctly installed in your L4D2 add-ons folder or that you've subscribed to it via Steam Workshop and allowed it to download fully. playbcm l4d2
Playing on PlayBCM is accessible to both Steam and non-Steam users: Скачать — PlayBCM If you are looking for the narrative plot