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.

Crusade is an American spin-off TV show from J. Michael Straczynski's Babylon 5. Its plot is set in AD 2267, five years after the events of Babylon 5, and just after the movie A Call to Arms. The Drakh have released a nanovirus plague on Earth, which will destroy all life on Earth within five years if it is not stopped. To that end, the Victory class destroyer Excalibur has been sent out to look for anything that could help the search for a cure.