Mission of the Viyrans (audio story)

 was a one-part story released along with The Mind's Eye. Unlike other one-part stories, it is not connected to the main story with which it was released nor does it have the same cast as the relevant story, given that this story does not feature Erimem, played by Caroline Morris. Nevertheless, it continued a virus strain story arc which concluded with Patient Zero.

Publisher's summary
The Doctor and Peri take a holiday on the planet Grallista Social, but soon discover they aren't the only time-travelling aliens in town.

Plot
to be added

Cast

 * The Doctor - Peter Davison
 * Peri Brown / The Viyrans - Nicola Bryant
 * Lawrence - Peter Sowerbutts
 * Chris - Philip Childs

Foods and beverages

 * Grallistan punch deserves its reputation for potency.

Individuals

 * The Viyrans attempt to wipe Peri's memories but they fail 338 times to achieve "Memory Zero."

Species

 * The Viyrans come from a galaxy which has known only war for millennia.

Continuity

 * Peri recalls her imaginary stepson Kyle (AUDIO: The Mind's Eye), meeting Dracula in Ungro-Wallachia in June 1462 (AUDIO: Son of the Dragon) and Erimem's departure from the TARDIS on Peladon in the 41st century (AUDIO: The Bride of Peladon).
 * During his sixth incarnation, the Doctor would later return to Grallista Social in the company of Charley Pollard. (AUDIO: Patient Zero)
 * The mutagenic virus which infected Peri was one of the millions of viruses which were accidentally released from the Amethyst Viral Containment Station in the far future and spread throughout time and space. (AUDIO: Patient Zero)