The first and only spinoff of Babylon 5.

In 2267 the Earth is quarantined, having been infected with a deadly plague by an attacking alien force. Scientists estimate that it will kill every inhabitant within 5 years, not nearly enough time for a cure to be developed. So the planet’s only hope lies with the Excalibur, an advanced prototype starship sent out to search ancient alien ruins for their former inhabitant’s secrets, hoping that somewhere out there a cure can be found.