The story is almost nada right now but your gonna have some flashbacks to another world or dimension (your not sure which), but your gonna find out one way or another even if you have to wade through the River Styx...

Features:
Open level
Excellent gameplay
Flashbacks
Beautiful TOD
Gorgeous level design

Installation instructions:
Browse to your Crysis level folder (Electronic Arts/Crytek/Crysis/Game/Levels).
Backup any existing levels with the same name.
Unpack the "Mountains" folder from the rar/zip archive into the level folder (Game\Levels).
Unpack the "Exodus Pines" folder from the rar/zip archive into the level folder (Crysis\Game\Objects\natural\trees).
Start Crysis.
Open the console, type in con_restricted 0 and press Enter, to allow access to all console commands.
Load the map by typing map mapname in the console and pressing Enter.

Additionally you can use the Crytools Launcher to load your custom level.