What defines Black Orchid in the history of Doctor Who is that it holds the title of being the last 'pure historical', story. It is a story which is set in the past and takes advantage of the Doctor's ability to travel in time but otherwise, not using science fiction as a platform to tell a story. In fact, not only is it the last pure historical but it is a weird anomaly, since these were kind of stories that the show stopped doing early on. Historical adventures where typically a William Hartnell thing, when the show's goal was the teach as well as entertain. By the time Patrick Troughton came along, the idea of the stories which Doctor Who could tell, had changed dramatically.
Something which I've noted before hundreds of times in these Doctor Who reviews, is that the show's format allows the main characters to be dropped into almost any genre. The Doctor could be at home in a historical setting, a robotic future or a Frankenstein movie. He could be a swashbuckler with a group of pirates. He could teach cavemen how to make fire or carry the Olympic torch. It wasn't until the purely historical stories died out that the show began to play around with these different genres: it didn't matter what story was being told, just so long as the Doctor and his companions were in it. For example, in modern times, the Tenth Doctor adventure, The Unicorn and the Wasp, tweaked the Agatha Christie/murder mystery genre to allow for a science fiction twist, the Doctor replaced the traditional detective while the wasp replaced the traditional killer. The Talons of Weng-Chiang with the Sherlock Holmes style of 1800's writing. But the science fiction element was always there, without that, you wouldn't have Doctor Who. During William Harnell's time on the show, the historical stories where the exception to that rule, but by the time Patrick Troughton was in the lead role, his second story, The Highlanders, was the only pure historical he did, they would constantly get lower ratings than any other show.
Except that Black Orchid turns everything I have just said, on its head. Usually what we would get was Doctor Who playing around with other genres. We get a slightly sci-fi feel when we see strangely disfigured hands and the bizarre appearance of a lip-plated Amazonian in an English country house. This story only pretends to follow a science fiction story. Nothing here is alien, it is all human-ish, though it comes with some rather outlandish explanations.
What Black Orchid ends up as is a non-Doctor Who story which just happens to feature the Fifth Doctor as a supporting character. It is a rather strange mixture of Jane Eyre and Sherlock Holmes, or Hercule Poirot-style murder mystery. Black Orchid is one of those murder mystery stories where who did it isn't really important but why they did it. Here, we get given a number of clues which don't fit in with the lives of people who live in a manor house in the countryside. We have a rare South-American flower called a Black Orchid, a missing and supposedly dead explorer and botanist who was last seen in the Amazon jungle, a very out of place Indian, a dead body in a cupboard wearing a male nurses' outfit and a strange and disfigured man who roams the halls of the house whenever he can. It is never anything but blindingly obvious who the murderer is, but that isn't really the point of the story. The real mystery here is what all these clues are leading up to, how the disfigured botanist George Cranleigh has come to be in their attic and whether or not the Doctor can figure out everything before he is irrevocably accused of murder. I suppose that because of the genre this story is playing with, it does greatly stretch the credulity of having a woman who looks like Nyssa involved and why the Doctor impersonates whoever was originally invited to play cricket. Oh, and why two Cranleigh brothers are engaged to the same woman and why two people are wearing the same harlequin costume.
And there isn't really a lot to the story itself, it is actually one of the shortest tales at the time when four episodes was the norm. This story runs for the length of one of the episodes from the modern series of the show, but it is paced far more leisurely as it freely takes plenty of time-outs and tangents. You could, I suppose, call it badly paced since the main bulk of the story doesn't get going until the second episode. But one can overlook that lack of plot because we get plenty of enjoyable character moments for each member of the TARDIS crew who were around during series nineteen. What makes this little factor so enjoyable is that character moments were never something which happened during the time of John Nathan Turner and Eric Saward on the show.
This is a rare chance to see the main cast cut loose and actually enjoy themselves. The biggest beneficiary of this is Janet Fielding as Tegan, who actually smiles for once and even dances instead of getting stuck in her usual role as a moaning mini. Sarah Sutton is also allowed to shake off some of Nyssa's wallflower tendencies and shows a more mischievous side. Even Matthew Waterhouse, although still annoying as the twerpy Adric gets in on the action, teased by the girls like a little brother for the amount of food they find him eating at various points of the tale. And it is amusing to see him failing to understand why he has to ask Nyssa or Mrs. Cranleigh to turn because he doesn't understand how women work.
And we even get an extra long scene where Peter Davison's Fifth Doctor gets to enjoy playing cricket. I suppose that was the show that his cricket costume wasn't just a stupid design, but to make him fit right in. In fact, he is a world class player, scoring a century in his first time at the bat. I guess putting a Doctor like the Fifth incarnation in the 1920s is perfect because not only does his costume make sense but because of Peter Davison's time in All Creatures Great and Small, which also happened to be John Nathan Turner's former home. The cricket scene gives Black Orchid a distinctively English taste, but it makes no allowances for those of us who know nothing about the sport. If you don't know who W.G. Grace was, you won't know his nickname was 'The Doctor', hence the momentary confusion in this story. And it is really unlikely that the two would have been mistaken for each other given that Grace looked like a member of ZZ Top!
Black Orchid is quite refreshing because it is a really low stakes story. It is just a couple of murders and a family who are harbouring a dark secret. It isn't anything which threatens the survival of the cosmos. And that is a really good thing because by having too many of those cosmic threats, could send the series into a state of stagnation, stories like this help to give the series a more human connection. It was also a story slight enough to probably have been condensed into one single episode. The ending of the story is perhaps a little too neat, with George Cranleigh falling to his death, not only paying for his own crimes but making those of his family irrelevant in the process - not least Lady Cranleigh's attempt to frame the Doctor for murder, something which could have meant the death penalty for him. I suppose it is lucky that the Fifth Doctor was the most forgiving of his incarnations.
The main problem with Black Orchid is that it is so wrapped up in it's Agatha Christie origins that it suffers from the same problems that The Talons of Weng-Chiang did, you can't restage something written in the early 20th century style - especially when the author's work are sometimes infamously racist. Black Orchid parallels traditional Doctor Who monsters with a non-white person and a physically and mentally disabled man and it doesn't do a good job of challenging the stereotypes which it capitalizes on. Latoni, the family's Indian guardian, turns out to be a loyal, intelligent, well-read and good natured person, not the baddie we were lead to expect with the way the first episode portrays him. The story does a worse job with its treatment of George Cranleigh. He is a tragic figure but the story comes dangerously close to saying that his horrifying ugliness is the same thing as being evil. While it never quite goes that far, it doesn't sit well in modern times. Lady Cranleigh is the real villain of the piece. None of this would have happened if she had taken better care of George and later admitted what he had done rather than trying to frame an innocent man.
Black Orchid certainly has its weird charms and is a nice breath of fresh air, amongst the cosmic-threats, we were given in every other story in series nineteen, it is good that it didn't inspire any future stories in the same vein. Nowadays, the story is an interesting curiosity and nothing more, a story which gives us a Doctor Who story which doesn't use any of the usual science fiction tropes. Of course, one could tell a story about Sherlock Holmes where he doesn't investigate a crime, or a story about Indiana Jones where he isn't after some artefact or another, but why would you really want to? Really, it was a waste of time putting this type of Hercule Poirot story in the Doctor Who universe. Sherlock Holmes solves crimes, that is what you want to read, The Doctor fights cosmic threats from space. That is what he does.
At the end of the day, Black Orchid gets away with the problems it caused because it was something which hadn't been done for a long time. But that sadly wasn't the point of the story, it is now just a superficial gimmick with deeper implications that neither John Nathan Turner and Eric Saward saw. Black Orchid doesn't explore what would happen if Doctor Who wasn't science fiction, certainly not to the extent the Tenth Doctor story, Human Nature/The Family of Blood did and definitely not to the extent the Star Trek: The Next Generation episode, Family, did with Captain Picard looking at the life he could have had after he was turned into a Borg drone in Best of Both Worlds. Both of these stories explore the lives that their main characters could have had if they had the choice not to be who they currently were. Black Orchid is nowhere near that ambitious and because of that, is nowhere near as interesting...