The Black Mesa facility was a secret research lab, owned and run by the "Black Mesa Research Facility Company." It was home to some of the best scientists in the world, and they were working on cutting-edge technology.

But then one day, everything went horribly wrong. The scientists were experimenting with a new type of matter called "Xen," and something went wrong. That led to a massive "resonance cascade" that opened a portal to the realm of Xen. Gordon ran out of the chamber and H.E.C.U Were deployed to action. gordons only objective is to get out alive.