Babylon 5 is a five-mile long space station located in neutral space. Built by the Earth Alliance in the 2250s, its goal is to maintain peace among the various alien races by providing a sanctuary where grievances and negotiations can be worked out among duly appointed ambassadors. A council made up of representatives from the five major space-faring civilizations - the Earth Alliance, Minbari Federation, Centauri Republic, Narn Regime, and Vorlon Empire - work with the League of Non-Aligned Worlds to keep interstellar relations under control. Aside from its diplomatic function, Babylon 5 also serves as a military post for Earth and a port of call for travelers, traders, businessmen, criminals, and Rangers.

A nuclear warhead launched by Soviet insurgents protesting the waning Cold War destroys the Ukrainian city of Donetsk. The destruction sets off a race between American and Soviet politicians to prevent a nuclear holocaust. While the U.S. president feverishly works to keep the military and political machine from going into overdrive, various subordinates panic. When the president is believed to be killed in a helicopter crash, zealous advisers take over.