Gordon Freeman

Gordon Freeman and his research team perform an experiment that inadvertently creates a dimensional rift in spacetime. Intelligent and confused alien life forms from the Xen dimension come pouring through multiple breaches inside the Black Mesa facility, attacking anything in sight. As scientific, military and civilian personnel fall under the alien onslaught, Freeman finds himself targeted not only by the xenomorphic incursion, but also the Hazardous Environment Combat Unit, a military team sent to contain the situation. The untrained theoretical physicist somehow manages to survive the chaos, impressing the few surviving scientists and security guards with his heroic acts, while quickly becoming the HECU's top priority target.