I don't know if Mark Gatiss wrote this as a pilot for a spin-off series for Madame Vastra and her entourage but it would work quite well in the capacity should the BBC decide a regular series mixing elements of Doctor Who and Sherlock by the same creators might be a hit. If he had, I doubt he could do better than this episode. A wonderful tribute to penny dreadful novels. As good as The Talons of Weng Chiang without any of the bothersome racist elements.
Yorkshire. 1893. Corpses are being pulled from the river with dark-red skin - a condition dubbed The Crimson Horror by those who have seen the bodies. This matter, while disturbing, does little to interest The Great Detective Madame Vestra until she is presented with a photograph of one of the victims' eyes, seemingly having captured the last thing the man saw... a screaming Doctor.
The trail leads to the town of Sweetville, where Jenny Flint infiltrates the evangelical community run by one Winifred Gillyflower and her blind daughter, Ada. What horrible secret lies at the heart of the seemingly perfect community, that prevents anyone from ever leaving? What terrible fate has befallen The Doctor, seemingly trapped within Sweetville's walls himself. And what of Mr. Sweet himself - Winifred Gillyflower's silent partner?
THE GOOD PARTS
* More Madame Vastra, Jenny Flint and Strax. Especially Strax! Here's hoping we can get a Doctor Who spin-off with the three of them at some point ala Torchwood.
* From the very beginning we know what we're in for - a penny dreadful in film form. Stylistically, the episode works well, with lots of gothic imagery and appropriately grotesque elements. Tragically scarred young women. Chained up monsters in the basement. Mysterious plagues chuckled at by hideous coroners. Apart from the time travel, there's nothing here that would be out of place in an Edgar Allan Poe story.
* Interesting note about Madame Vastra's residence - it has a blue door that looks like The TARDIS.
* Another reference to the classic series, as The Doctor tells Clara (who complains about how inaccurate The TARDIS is) that it's much better than it used to be and how he once spent an unbelievable amount of time trying to get "a gobby Australian" to Heathrow airport. Clearly a reference to Tegan - a stewardess accidentally abducted by the Fourth Doctor, who became The Fifth Doctor's most frequent companion.
* "Brave heart, Clara". Another nod to Tegan, as "Brave heart, Tegan" was The Fifth Doctor's frequent admonishment to Tegan whenever she complained about something dangerous occurring. It's funny because Clara reminds me a bit of Tegan out of all the classic series Companions in terms of personality, being argumentative and more often disturbed than not about all the strangeness around her.
* Another classic series nod - Doctor and Mrs. Smith as an alias.
* Dame Diana Rigg - Miss Peel herself - is a magnificently melodramatic villain.
* Talking of Miss Peel - awesome moment with Jenny stripping down to reveal her leather catsuit before showing off her martial arts skills.
* Much as I love Madame Vastra and company, something did just occur to me thinking of them starring in a Torchwood-style spin-off - where the bloody hell is Torchwood right now? I checked the dates and Torchwood was established roughly a decade before we started seeing The Great Detective, her wife and their Sontaran butler. Even if we accept that they can't openly move against Madame Vestra due to her prominence in the city, you'd think they'd take an interest in red-skinned bodies turning up in the river. (Maybe they're not as powerful as they once were in the current timeline due to... timey wimey stuff?)
* I'm not sure having a girl pretend to faint three feet away from you is an effective distraction when you're attempting to pick a lock in a hurry, at least in my considerable experience playing fantasy RPGs.
* The final two minutes or so with Clara returning home and being confronted by children she's watching.. How the heck did the kids find all the pictures of her on the Internet, much less make the leap to "your boyfriend has a time machine"? Why is there a full color picture of the Victorian London Clara? (An adventure Clara had in the past that hasn't happened to her yet?) Besides, how exactly is telling her father that the babysitter is a time-traveler a threat? Would their dad really take them seriously? Honestly, this plot development would worry me save for one thing - the next episode involving the kids is written by Neil Gaiman and I trust him to find a way to make this magical.
THE FINAL VERDICT
It would have been a perfect episode had it ended two minutes earlier with Madame Vastra's client fainting as The TARDIS disappears. Still a great episode in spite of the seemingly tacked-on ending we got.