Trying to transport Tegan to Heathrow airport on present-day Earth, The TARDIS accidentally lands on-board a alien spaceship traveling to Earth which will arrive in 4 days. Where the Doctor, Adric, Nyssa and Tegan encounter the frog like Monarch, ruler of the doomed planet Urbanka. Only to find Monarch has abducted generations of humans from different cultures and converted them into cyborgs. The Doctor and Tegan discover Monarch's true goal is to travel faster than the speed of light, and traveling back into time where he will meet himself and wipe out the human race, repopulating the Earth with his own race. Written by
Did You Know?
The episode establishes the date of Logopolis and the opening scenes of Doctor Who: Castrovalva: Part One
(1982) by revealing that the flight Tegan was trying to catch in Logopolis was flight A778 at 1730 on 28 February 1981. This retroactively set Logopolis on the same date as it was broadcast. See more
Is it usual for a host to kill a guest?
Oh, in certain rarified circles.
Featured in A New Body at Last