This episode, the tenth of the series, begins with the crash of a mysterious object in Townsend, Wisconsin. The U.S. Space Surveillance Center, which according to Deep Throat tracks all objects that enter American air space, have determined that the object – due to its erratic flight path and maneuverability – is not any aircraft that they are aware of.
This triggers ‘Code Indigo,’ which leads to ‘Operation Falcon,’ led by Col. Henderson (Marshall Bell), who is tasked to handle such matters.
Operation Falcon is designed to kill any extraterrestrial entity that’s discovered, which ‘Deep Throat’ later informs Mulder has been going on much longer than he may be aware.
“Fallen Angel” starts off as a solo adventure, till Mulder, after being captured by Henderson, is aided by Scully.
The most notable thing about the episode is the introduction of ‘The Lone Gunmen,’ who always bring a welcome dose of levity (and paranoia) to the proceedings.