Doctor Who: The Underwater Menace, Episode 3 (1967)

In the third episode of the four-part story "The Underwater Menace," the Doctor (Patrick Troughton) steps up his efforts to thwart the world-destruction schemes of Professor Zaroff (Joseph Furst). He is able to foment a below-the-sea rebellion against Zaroff, utilizing an army of fishlike ex-slaves -- but the results are far from satisfactory. Written by Geoffrey Orme, Doctor Who: The Underwater Menace, Episode 3 was first telecast on January 28, 1967. This is the only one of the four episodes known to exist in the BBC archives. ~ Hal Erickson, All Movie Guide