The Half-Life series begins in the year 1998, at the fictional Black Mesa Research Facility in New Mexico. Dr. Gordon Freeman, a recently employed theoretical physicist, is involved in an experiment analyzing an unknown crystalline artifact; however, when the spectrometer beam contacts the crystal, it opens a dimensional rift between Black Mesa and another universe called Xen, causing monsters to swarm Black Mesa and kill much of the facility's personnel. Attempts by the Black Mesa personnel to close the rift are unsuccessful, leading to a specialist US Marines unit being sent in to silence the facility, including any survivors from the science team. Freeman fights through the facility to meet with several other scientists, who decide to travel to the alien