Marine black operations units to silencing the witnesses. The government, however, already has plans to contain this incident by sending in U.S. When Freeman, the survivors, and security guards discover the portal has allowed its inhabitants-deadly alien creatures-to enter the facility, they call the government for help.
Gordon blacks out, and awakes in a now crippled and ruined research facility.
Believing they are under attack from the Combine the enslaved creatures of Xen go on the offensive. Gordon Freeman is assigned to physically test the artifact, things go very wrong when the artifact opens a destructive and unstable portal to Xen. A mysterious alien artifact has been recovered and brought to a top-secret research facility in the Black Mesa facility in New Mexico.
