You were bored and decided to look at the Garry's mod workshop when something caught your eye, the mysterious mod called "RAIDS" you decide to install it, it fully downloads and you hop on Garry's mod and load into a map with enough AI nodes, you opened the console menu and typed "raids_server_combine_assault 1" you saw nothing yet, so you decided to roam around the map

Game starts.. Good luck soldier, keep in mind that there's a strong combine soldier somewhere and the combine limit continues to rise every minute..