The Invisible Enemy (Doctor Who)

093 – The Invisible Enemy
Doctor Who serial
Cast
Others
Production
Directed byDerrick Goodwin
Written byBob Baker
Dave Martin
Script editorRobert Holmes
Produced byGraham Williams
Executive producer(s)None
Music byDudley Simpson
Production code4T
SeriesSeason 15
Running time4 episodes, 25 minutes each
First broadcast1–22 October 1977
Chronology
← Preceded by
Horror of Fang Rock
Followed by →
Image of the Fendahl
List of episodes (1963–1989)

The Invisible Enemy is the second serial of the 15th season of the British science fiction television series Doctor Who, which was first broadcast in four weekly parts on BBC1 from 1 to 22 October 1977. The serial introduced the robot dog K9, voiced by John Leeson. In the serial, an intelligent virus intends to spread across the universe after finding a suitable spawning location on the moon Titan.