In the universe of Half-Life, Nick Farrell is a technical engineer working at Delta Base — a research facility that has been competing with Black Mesa across multiple fields, including the investigation of the borderworld Xen and the development of new weapons. Two different experiments are running simultaneously when something goes wrong in the coupling between them. The resulting resonance cascade reaches Delta Base as it did Black Mesa. The hostile alien lifeforms arrive shortly after and do not take long to spread through the facility.