AEGIS was formed the day of the Roswell Incident in 1947 to defend the United States, Humanity, and the Earth from all enemies, Foreign, Domestic, and Extraterrestrial.

The National Defense Directorate ("The Black Book") was formed the day of the Roswell Incident in 1947 to keep secure the United States from all enemies Foreign, Domestic, and Extraterrestrial by Any Means Necessary.

The Strategic Homeland Intervention Enforcement Logistics Division (SHIELD) was formed in 1953 from the Allies' Strategic Scientific Reserve (SSR) that had itself been formed in 1939. SHIELD's mission is to defend Humanity and Earth from major Threats To The Peace (T3P), both Terrestrial and Extraterrestrial in origin.

The year is 2024. Saurians are getting antsy, the Reticulans are making moves, the Atlanteans are interfering more than usual, and then there's the new stuff SHIELD tends to handle overseas.

This is using the Conspiracy X 1.0 ruleset, although there are considerable modifications, especially to Character Generation.