Big Finish Doctor Who/Recap/136 Cobwebs

Cobwebs was the first time that nearly all of the classic Fifth Doctor companions (excluding Adric) shared the same stage since 1982's Terminus. The TARDIS, carrying The Doctor, Tegan and Turlough, is pulled towards the abandoned Helheim Genetic Research Facility, an isolated medical lab located at the edge of the galaxy, where a team of doctors worked tirelessly to find a cure for Richter's Syndrome, a contagious disease that was ravaging the galaxy. At the same time, Nyssa of Traken, 50 years older than when we last saw her, is investigating the same facility. There, the reunited TARDIS team finds skeletons of themselves, covered in cobwebs, sealed in a medlab, apparently undisturbed for 46 years...

Tropes

 * AI Is a Crapshoot: EDGAR. Pity him. May also qualify as Friend Computer (a very depressing friend, to be sure).
 * And the Adventure Continues: While Nyssa is keen to get back to work curing the genetically-modified Richter's Syndrome, she takes advantage of the TARDIS' rather... idiosyncratic... approach to direction to stick on with her old friends for a while.
 * The Eeyore: LOKI, EDGAR (pity him) and to a lesser extent Turlough all qualify.
 * Long Bus Trip: At least from Nyssa's point of view -- for her, it's been 50 years since she last saw The Doctor, Tegan and Turlough. For the rest, it's been two days since they left her on Terminus.
 * Madness Mantra: "Pity poor EDGAR..."
 * Mind Rape: The memory devices on Helheim can do this as a defense mechanism. All you have to do is create unpleasant memories, record them, and have EDGAR (pity him) replay them at a predetermined point when intruders show up.
 * Grandma What Massive Hotness You Have: Nyssa is, at least in human years, somewhere around 70. She doesn't look much over 50 (conveniently, close to Sarah Sutton's actual age) due to the fact that Trakenites age slower than humans, and according at least to Tegan, looks quite good for her apparent age at that.
 * Oh My Gods: Mixed with a touch of Anachronism Stew -- The Helheim staffers seem to worship the Norse pagan pantheon, or at least swear by various Viking gods.
 * Red Herring: The alien ruins found by the Helheim team. While they seem to be setting up for a key part in the mystery, they end up being little more than Paranoia Fuel for one of the scientists.
 * Robot Buddy: LOKI.
 * Shout Out: To Star Wars -- LOKI is called "R2D2" by Tegan, and acts a whole heck of a lot like C-3PO.
 * Stable Time Loop: the resolution to the plot depends on it.
 * Timey Wimey Ball: One of the best examples not done by Steven Moffat.
 * What About the Alien Ruins?