Colonel Elizabeth Lochley (Tracy Scoggins) calls in a priest, Father Cassidy (Alan Scarfe), to come to Babylon 5 to aid in the possible possession of maintenance worker, Simon Birk (Bruce Ramsay). The entity possessing Birk wants to be excorcised, and is trying to force Father Cassidy to excorcise him. Colonel Lockley figures out that the entity possessed Birk while he was on a visit to earth, after which Birk had hitchhiked to Babylon 5. Now the entity now wants to be released from him via the excorcism. Colonel Lockley also deduces that the entity had been imprisoned on earth and is unable to leave. She decides to send Birk back to earth so the entity cannot escape.