The Doctor and Romana are hiding from the Black Guardian in 1920s London, having taken a townhouse and adopting the roles of a lord and lady while the TARDIS (containing K9) completes multiple random journeys as a diversion. When the Doctor builds a machine to detect energy signals as a warning device, he becomes aware of an alien presence in Hampshire. Meanwhile, Romana has encountered a feckless young aristocratic gentleman, Reginald, and this leads her into an encounter with the same creature, which is posing as the man's Auntie Florence, Lady Bassett. With the maid, Mabel Dobbs, in tow, the Doctor investigates and the two Time Lords must contend with murderous (but faultlessly polite) robot servants and their pitiless mistress, who preys on young women, and has Romana lined up as the next victim.

• The Doctor – Tom Baker
• Romana I – Mary Tamm
• Aunt Florence – Julia McKenzie
• Reggie – Robert Portal
• Mabel Dobbs – Lucy Griffiths
• Grenville – Alan Cox
• Ligeia – Jane Slavin

• This is the first of seven releases reuniting Tom Baker and Mary Tamm as the Fourth Doctor and First Romana. Tamm died in July 2012, but completed all seven productions before her death.^[1]

• The Auntie Matter