Babylon 5: The Lost Tales - Voices in the Dark (2007)

This instalment of Babylon 5 is in two parts: the first is about an entity that has possessed a worker. Colonel Lochley prevents a priest from performing an exorcism. The host is returned to Earth. The second has Galen trying to dupe President Sheridan into assassinating the future Centauri emperor to stop him from attacking Earth in around 30 years time.