Rat Trap (audio story)

 was the one hundred and forty-eighth story in Big Finish's monthly range. It was written by Tony Lee and featured Peter Davison as the Fifth Doctor, Sarah Sutton as Nyssa, Janet Fielding as Tegan Jovanka and Mark Strickson as Turlough.

Released in June 2011, it was the final story in the 2011 Fifth Doctor trilogy featuring Tegan, Turlough and an older Nyssa.

Publisher's summary
1983: as the country goes to the polls, two "Urban Explorers", together with a freelance journalist, break into the long-defunct Cadogan Tunnels, once a secret wartime facility... and later, so rumour has it, the site of an experimental laboratory with a nasty sideline in vivisection.

What they find, in its twisting underground corridors, is something the most cynical conspiracy theorist could never have imagined: a highly-evolved society of questing, intelligent creatures, living right under humanity's nose for decades.

But there's no way out of the tunnels — as the Doctor, Nyssa, Tegan and Turlough are about to discover when the TARDIS brings them, too, into the complex. It's a rat trap — and they've all been caught!

Plot
to be added

Cast

 * The Doctor - Peter Davison
 * Nyssa - Sarah Sutton
 * Tegan - Janet Fielding
 * Turlough - Mark Strickson
 * Clifford Andrews - John Banks
 * Sally Lucas - Alison Thea-Skot
 * Dr. Christopher Wallace / The Rat King - Terry Molloy
 * Kevin - David Seymour
 * Matthew / Major Harris - Andrew Dickens
 * Caitlin Jones - Charlie Norfolk

Organisations

 * The Doctor tells Nyssa that UNIT will clean up after him, and tells Kevin he'll contact them in order to see if he could join up.

Politics

 * British Prime Minister Margaret Thatcher is mentioned several times. The Doctor notes that the 1983 general election will be a "landslide" for the Conservative Party.

TARDIS

 * Turlough refers to the State of Grace in the TARDIS and how it will prevent weapons fire but not general damage.

Continuity

 * Nyssa refers to her visit to Stockbridge in 1199 and her memories of knights in armour. (AUDIO: Castle of Fear)
 * The rats mention the Mara to Tegan. (TV: Kinda, Snakedance; AUDIO: The Cradle of the Snake)
 * One of the rats refers to Nyssa's experiments on the Cractids in the 36th century. (AUDIO: Cobwebs)
 * The rats exploit Nyssa's anger at for killing her father Tremas and her stepmother Kassia. (TV: The Keeper of Traken)
 * The Helheim cure is destabilising. (AUDIO: Cobwebs)
 * Turlough uses a spark wire from Purity. (AUDIO: The Whispering Forest)