In the fourth episode of the season-long continuity "The Trial of the Time Lord," the Valeyard (
Michael Jayston) uses videotaped evidence in hopes of proving that the Doctor (Colin Baker) was guilty of breaking the Laws of Time on the planet Ravolox. But the Doctor contends that he and his companion, Peri (Nicola Bryant), were actually responsible for saving Ravolox from the villainous machinations of intergalactic con artist Glitz (Tony Selby). Written by Robert Holmes and originally telecast on September 27, 1986, Doctor Who: The Trial of a Time Lord, Episode 4 was technically the concluding chapter of a four-part story arc subtitled "The Mysterious Planet." ~ Hal Erickson, All Movie Guide