Welcome to London at the dawn of the eighteenth century, where young men of varied character are disappearing, while blackguards and Phatasmagoria roam, frightening the unwary. Amidst this, the Fifth Doctor and Turlough pick their way through an intriguing plot...
Gatiss has written a solid adventure, richly textured with atmosphere and character, both of which are given plenty of time to develop before the story starts to bite. We are introduced to the various players in this mystery expertly and satisfyingly, the sketchiness of some relevant to the plot. The Doctor himself seems to be a comfortable portrayal, Peter Davison giving a slightly more mature performance than on screen, while Turlough doesn't seem to quite fit. His character is largely there, but some of his more striking elements, such as his sense of self-preservation, seem to have been played down or ignored, presumably to serve the plot, which requires more of him than you would have expected. It actually feels a little as though the script has been tweaked to allow for actor availability rather than written specifically for him.
Supporting characters fare somewhat better, a sort of proto-Jago and Litefoot being the main support: a man of eloquence but dubious character working with Turlough, while a doctor with a penchant for the occult providing support and clues to the Doctor. The actors get themselves round the occasionally prosaic language admirably, using horrendously obscure terms on occasions, but thankfully in a context that generally allows you make make sense of them.
In the end, script, cast and production all largely gel, producing a solid, if slightly unremarkable adventure that's worth a listen, if only to enjoy Mark Gatiss' occasional quirky use of language.