New Main Range 35:
Doctor: 5
Companions: Death, Turlough, Tegan
Fifth Doctor is on a boat in the 80s with Turlough when he dies after being eaten by a shark. The Doctor barely notices at first because he’s lost the fishing rod under the lake Five pleads with Death to let Turlough live and Tegan wants him dead.
Turlough spends a lot of the audio play as a ghost and for the first part, nothing suspicious goes on, it’s a regular investigation in a town that previously had a drought; The Doctor decides to go fishing because of the nice weather, Tegan decides to grump about on land because she can’t enjoy the lovely time with Nyssa because she’s gone and the gay snake inside her is causing her to repress this and try being heterosexual so she decides to go on a date with a mysterious local instead, who also sounds Australian.
Eventually The Doctor stops trying to save Turlough and simply gives up, assuming the laws of time make his death set in stone.
Tegan gives them a good talking to and reminds him of Adric. They both start to save Death but as a result, she is bound to the Doctor again and has to help them solve the drought while also not killing people (think C’rizz mixed with Leela for dynamic)
Also the heterosexual love interest that Tegan was with for part of the story is revealed to have been part of a cult worshipping Abaddon and unfortunately the machine happens to implode due to the entire mechanism having been broken by the fishing rod failure in Part 2.
Death looks like she’ll betray them for Abaddon at the climax of Part 5 but she doesn’t; believing in the Doctor, who nonsensically asks them to turn on the machine anyway, after Turlough shouts at him asking to.
Turlough is also slightly in love with Death and chooses to disobey the Black Guardian because A: He was getting on well as a ghost and B: He didn’t want to go fishing anyway.
The Black Guardian vows revenge and this is implied to be why Turlough shouts for The Doctor to turn on the machine.
At the end, after the companions have gone to bed, there is a scene where The Doctor and Death have to make a similar deal again, implying that The Master would have reverted to good due to being in Nyssa’s dad.
It is a rather self-contained audio, other than ties to the Fifth Doctor’s era, other Big Finish Audios containing Death and generally having been made as a tie in to the earlier New Main Range audio “Come along, Death” by @RandomJoke
(Name of audio open to suggestion.)