Garry’s Mod is a sandbox mod for the Source Engine. Unlike normal games there aren't any predefined aims or goals. Players are given tools and are left to entertain themselves. The player is in a world where objects can be created and destroyed on demand. Where people can be created and destroyed with the click of a mouse. A world made for him. A world he made.
The Dark Angels deliver the righteous fury of the Imperium onto the Combine xenos and their traitorous human collaborators in City 08 to liberate it and the alternate version of Holy Terra it lies on from the Combine's iron grip.