A highly advanced alien species known as the Combine have taken over Earth, quickly subjugating most of the population. A small sliver of humanity still resists, in the hopes that the right ally could help push back the Combine and tip the balance in humanity’s favor. The player reprises their role as Gordon Freeman, who mysteriously appears in the heart of Combine occupied territory. With no support, Freeman must navigate the alien environment and make use of any resources he can to help his allies.