The Enchantress of Numbers (audio story)

 was the third story in the eighth series of the Fourth Doctor Adventures, produced by Big Finish Productions. It was written by Simon Barnard and Paul Morris and featured Tom Baker as the Fourth Doctor and Jane Slavin as Ann Kelso.

Publisher's summary
The TARDIS lands in the grounds of Newstead Abbey, Nottinghamshire, in 1850. Mistaken for a medic and his maid, the Doctor and Ann are brought to meet Ada Lovelace - the mother of computing and daughter of Lord Byron - who has recently fallen ill. But the travellers are not here by chance. Something odd is happening on Earth, and they’ve determined that this place is the centre of it. Strange figures are walking the land. Strange figures wearing bird-like masks. What do they want with Ada? And how will it change the future of humanity?

Part one
to be added

Part two
to be added

Cast

 * The Doctor - Tom Baker
 * Ann Kelso - Jane Slavin
 * Ada Lovelace - Finty Williams
 * Colonel Wildman - Andrew Havill
 * Hettie / Lady Cleverley - Eve Webster
 * Mr Hobhouse - Barnaby Edwards
 * Edvard Scheutz / Lord Byron / Harry - Glen McCready

Continuity

 * The Doctor would met Ada again at an earlier point in her timeline in his thirteenth incarnation, but Ada's memories of that encounter were wiped. (TV: Spyfall)