The Doctor becomes increasingly suspicious of Ian and Barbara but when the occurrences aboard the TARDIS become even stranger he realises they are in even greater danger than they realised.

Starring:

Elisabeth Sladen, Frazer Hines, Jacqueline Hill, John Levene, John Scott Martin, Jon Pertwee, Katy Manning, Nicholas Courtney, Pat Gorman, Patrick Troughton, Peter Davison, Tom Baker, William Hartnell, William Russell

Genre:

Adventure, Drama, Sci-Fi