The Defectors (audio story)

 was the 198th story in Big Finish Productions' Doctor Who monthly range. The beginning of the "Locum Doctors" trilogy, it partnered the Seventh Doctor with Third Doctor companion Jo Grant.

Publisher's summary
Jo Grant is shocked to find most of her colleagues are missing. Then she discovers that the Doctor has inexplicably changed.

But there’s little time to worry about it all, as she and her misplaced Time Lord friend are whisked to the mysterious Delphin Isle on a matter of national security. There, they encounter a disturbingly odd form of local hospitality and learn of a highly classified incident that took place during the Cold War.

Why exactly have they been brought here? And what is the truth concerning the bodies in the harbour and the vast project being undertaken under a cloak of secrecy?

Plot
to be added

Cast

 * The Doctor - Sylvester McCoy
 * Jo Grant - Katy Manning
 * Captain Yates - Richard Franklin
 * Captain Cornelius - Neil Roberts
 * Commander Wingford - Barnaby Edwards
 * Shedgerton - David Graham
 * Europan Leader - Rachel Bavidge
 * Europan - Jez Fielder
 * Brigadier Lethbridge-Stewart - Nicholas Courtney (archive recording)

Continuity

 * The aliens arrived in 1951, which was "nearly 30 years ago" according to Jo, dating this story to around the late 1970s. (See: UNIT dating controversy)