From the introduction: In the early months of 2015 we were visited by aliens. They took innocent humans and ran horrific experiments on them. The aliens decided to stay, and quickly proceeded to attack the nations of earth. The XCOM project was started by the Council of 16 and placed under the command of a singular individual. It was to be humanities last, best hope at defeating the invaders. To create weapons and tactics that would destroy the technologically superior foe. It failed.