The Doomsday Chronometer (audio story)

 was the third story in the audio anthology Doom Coalition 3, produced by Big Finish Productions. It was written by Matt Fitton and featured Paul McGann as the Eighth Doctor, Nicola Walker as Liv Chenka, Hattie Morahan as Helen Sinclair and Alex Kingston as River Song.

Publisher's summary
While River Song takes Helen on an archaeological expedition like no other, the Doctor finds himself enlisted by an alien Queen to save her people.

Trapped and alone, Liv stares death in the face as she meets the enemy who's been dogging the TARDIS travellers' footsteps throughout Earth's history.

The Doomsday Chronometer has been protected for five centuries: secret cults and societies jealously guarding its mystery. But what is their real purpose? The Doctor is about to discover the truth…

Plot
to be added

Cast

 * The Doctor - Paul McGann
 * Liv Chenka - Nicola Walker
 * Helen Sinclair - Hattie Morahan
 * River Song - Alex Kingston
 * Thomas Cromwell - John Shrapnel
 * Solvers - Glen McCready
 * Rosalia - Emma D'Inverno
 * Octavian - Tim McMullan
 * The Clocksmith - Nicholas Woodeson
 * Risolva - Janie Dee

Continuity

 * River mentions she knew another Octavian once, who was part of another church. (TV: The Time of Angels)
 * Liv recognises River as professor Malone. (TV: The Angels Take Manhattan, AUDIO: The Sonomancer)
 * The destruction of the planet Syra is mentioned. (AUDIO: The Sonomancer)
 * River tells Helen to have the Doctor take her to Versailles one day, but to avoid Madame de Pompadour. (TV: The Girl in the Fireplace)