Patient Zero (audio story)

 was the one hundred and twenty-fourth monthly Doctor Who audio story produced by Big Finish Productions. Released in 2009, it featured Colin Baker as the Sixth Doctor and India Fisher as Charley Pollard.

Publisher's summary
Finally, the Sixth Doctor challenges Charlotte Pollard to tell him the truth. Who is she really? What is she doing in the TARDIS?

To discover the answers, the Doctor must travel back in time, beyond all known civilisations to the vast, mysterious Amethyst Viral Containment Station. But answers lie within the TARDIS too. Someone who has been there a long, long time...

Meanwhile, the Daleks have travelled back in time on their own mission, to bring them the ultimate victory they crave. But it is a mission so complex and delicate that even they know they must beware the web of time...

Who is Patient Zero? What has happened to Charley? And why have the legendary Viyrans been summoned?

Plot
to be added

Cast

 * The Doctor - Colin Baker
 * Charley Pollard - India Fisher
 * Fratalin - Michael Maloney
 * Mila - Jess Robinson
 * Etheron/The Daleks - Nicholas Briggs

Daleks

 * The Dalek Time Controller is a Dalek that directs Dalek strategies involving time travel, while preventing its destabilisation.

Individuals

 * Mila is the first person that the Daleks infected with their Virus 7001.
 * The Sixth Doctor travelled for a substantial number of years searching for a cure for Charley's condition.

Species

 * The Viyrans are tasked with a mission of peace: the destruction of biological weapons.

Continuity

 * The Doctor places Charley in the Zero Room to stabilise her condition. (TV: Castrovalva et al)
 * Mila has been in the TARDIS since the Daleks were chasing the Doctor through time. (TV: The Chase)
 * Mila refers to previous Dalek stories TV: The Dalek Invasion of Earth, The Chase, The Daleks' Master Plan, The Power of the Daleks and The Evil of the Daleks.
 * One of the viruses would make it to Earth. (AUDIO: Blue Forgotten Planet)
 * The method used here to stop the Daleks from dematerialising Amethyst was similarly used to prevent the Captain from materialising Zanak around Earth at the end of the story. At the start the reverse happened as the Captain stopped the TARDIS from materialising on Calufrax. (TV: The Pirate Planet)
 * Although the Doctor believed that he had killed the Dalek time controller, it survived and travelled back through the Time Vortex to the 22nd century where it was discovered by the Daleks of that era. With the assistance of the renegade Time Lord, the Monk, the Dalek time controller planned to install a time warp engine in the core of the Earth and pilot the planet, which was to have become a plague planet teeming with the Amethyst viruses, through time and space. However, it was defeated by the Eighth Doctor, his granddaughter Susan Foreman, his great-grandson Alex Campbell and his former companion Lucie Miller, though both Alex and Lucie were killed in the process. (AUDIO: To the Death) The Doctor later encountered it once again on Srangor. (AUDIO: X and the Daleks)
 * The viruses released from the Amethyst Viral Containment Station include a bio-engineered telephone virus (AUDIO: Urgent Calls), a mutagenic virus (AUDIO: Mission of the Viyrans) and Virus 7001B which was sent back in time to the beginning of the universe and resulted in the creation of life itself (AUDIO: The Viyran Solution).