The story is set on the planet Lakertya where the Rani is building a super-brain. To assist her in this enterprise, she has kidnapped a number of geniuses, including Louis Pasteur and Albert Einstein.
The story was written by Pip and Jane Baker and directed by Andrew Morgan. The cast also includes Karen Clegg (Sarn), Richard Gauntlett (Urak), Mark Greenstreet (Ikona), Donald Pickering (Beyus), John Segal (Lanisha), and Wanda Ventham (Faroon).
See also List of Doctor Who serials