by Hal Erickson
synopsis
In the conclusion of the four-part story "The Greatest Show in the Galaxy," the three evil rulers of the Psychic Circus, disguised as a "typical" tourist family, demand entertainment from the Doctor (Sylvester McCoy) and Ace (Sophie Aldred) -- threatening instant death if that entertainment is not forthcoming. In trying to escape this fate, the Doctor activates the fabled "Old Devil Moon" effect, with startling consequences. Written by Stephen Wyatt, "The Greatest Show in the Galaxy, Episode 4" first aired on January 4, 1989, as the final episode of Doctor Who's 25th season.
