The Doctor is summoned to the Victorian era once again by Madame Vastra and her colleagues. People are signing up to become model residents of a walled-off, gated community promising traditional values… and then, once accepted, they are never heard from again. The Doctor and Clara pose as another perfect couple hoping to become residents of Sweetville, and their application is quickly accepted. Once inside the gates, though, the time travelers learn that residency in Sweetville carries a horrifying cost, one which puts them out of the picture. Now the fate of humanity, and the Doctor, rests with the Doctor’s unlikely trio of allies.
written by Mark Gatiss
directed by Saul Metzstein
music by Murray GoldCast: Matt Smith (The Doctor), Jenna-Louise Coleman (Clara), Dame Diana Rigg (Mrs. Gillyflower), Rachael Stirling (Ada), Catrin Stewart (Jenny), Neve McIntosh (Madame Vastra), Dan Starkey (Strax), Eve de Leon Allen (Angie), Kassius Carey Johnson (Artie), Brendan Patricks (Edmund / Mr. Thursday), Graham Turner (Amos),
Olivia Vinall (Effie), Michelle Tate (Abigail), Jack Oliver Hudson (Urchin Boy)
Notes: Dame Diana Rigg is one of the most recognizable faces of British TV, having co-starred as Mrs. Peel in The Avengers with Patrick Macnee for several seasons. (Her predecessor as Steed’s sidekick, Honor Blackman, had a guest starring role in parts 9-12, a.k.a. Terror Of The Vervoids, in 1986’s The Trial Of A Time Lord.) The BAFTA, Tony, and Emmy-winning actress has also appeared in the James Bond movie On Her Majesty’s Secret Service, and more recently in Game Of Thrones. Actress Rachael Stirling is Rigg’s daughter and a well-regarded actress in her own right, having appeared in Minder, Tipping The Velvet, Hotel Babylon, and Snow White & The
Huntsman.
The Doctor mentions traveling with an air stewardess who wanted to return to Heathrow; this is a rare reference to Tegan Jovanka, the Australian companion of the fourth and fifth Doctors. Though the character has been revived by actress Janet Fielding for the Big Finish audio adventures, this is the first mention of Tegan in the new series. (She was also mentioned in the laundry list of former TARDIS travelers and their respective outcomes in part two of the Sarah Jane Adventures story The Death Of The Doctor (2010).
LogBook entry & review by Earl Green
Review: A decidely odd attempt to do a non-linear narrative that makes an otherwise straightforward story seem a bit shocking and confusing, The Crimson Horror starts out as 
another showcase for Strax, Madame Vastra, and Jenny, spotlighting them as they try to free the Doctor from his predicament. As much as they’re basically comedy characters, they’re actually very effective here – it’s almost a pilot for a spinoff featuring that trio of characters. As goofy as the Doctor seems after a few minutes of Matt Smith being painted red as a lobster, it’s easy to think “Hey, I’m ready for this spinoff now.”
The surprisingly big-name guest star for this episode is Dame Diana Rigg, who surely needs no introduction. That she is most assuredly 
not one of the good guys is the icing on the cake, since she gets to chew some scenery as the fiercest uptight traditionalist this side of Downton Abbey’s Dowager Countess. (Actually, that’s an epic face-off I’d pay good money to see, now that I think of it: an all-spinster spinoff.) I’m a little less thrilled with her squidgy, squooshy, puppet-y sidekick, Mr. Sweet, but that character is effective in its own right – sort of like the Claymation mind-control invaders from the Star Trek: The Next Generation episode Conspiracy, there’s something undeniably disgusting about it, even if there’s a disconnect between the execution and the conceptualization. In the end, it’s disgusting enough when Mr. Sweet gets his comeuppance, and that’s enough. (On the flipside of Mr. Sweet’s exit is the sight of Strax barrelling into a scene, gun a-blazing, cackling gleefully.)
All spinoff talk aside, though, what remains to be done with Madame Vastra and her motley crew is to deposit them in a different time zone where their Victorian modus operandi makes them even bigger fish out of water. Or, perhaps even more adventurous would be to have them butt heads with Victorian-era Torchwood (complete with the just-recruited, massive-sideburned Jack Harkness). Then again, as of The Crimson Horror, these three have saved the Doctor. Is there any situation with which they can’t cope?