The Doctor - Matt Smith
Clara - Jenna-Louise Coleman

Mrs Gillyflower - Dame Diana Rigg
Ada - Rachael Stirling
Jenny - Catrin Stewart
Madame Vastra - Neve McIntosh
Strax - Dan Starkey
Angie - Eve De Leon Allen
Artie - Kassius Carey Johnson
Edmund & Mr Thursday - Brendan Patricks
Amos - Graham Turner
Effie - Olivia Vinall
Abigail - Michelle Tate
Urchin Boy - Jack Oliver Hudson

Stunt Coordinator - Crispin Layfield
Stunt Performers - Stephanie Carey, Daniel Euston

First Assistant Director - Nick Brown
Second Assistant Director - Heddi-Joy Taylor-Welch
Third Assistant Director - Delmi Thomas
Assistant Director - Daneille Richards
Location Manager - Iwan Roberts
Unit Manager - Monty Till
Location Assistant - Iestyn Hampson-Jones
Production Managers - Phillipa Cole, Claire Hildred
Production Coordinator - Gabriella Ricci
Production Secretary - Sandra Cosfeld
Production Assistants - Rachel Vipond, Samantha Price
Assistant Accountants - Rhys Evans, Justine Wooff
Assistant Script Editor - John Phillips
Script Supervisor - Steve Walker
Camera Operator - Joe Russell
Focus Pullers - James Scott, Julius Ogden
Grip - Gary Norman
Camera Assistants - Meg De Koning, Sam Smithard, Evelina Norgren
Assistant Grip - Owen Charnley
Sound Maintenance Engineers - Ross Adams, Chris Goding
Gaffer - Mark Hutchings
Best Boy - Stephen Slocombe
Electricians - Bob Milton, Gafin Riley, Gareth Sheldon
Supervising Art Director - Paul Spriggs
Set Decorator - Adrian Anscombe
Production Buyers - Adrian Greenwood, Holly Thurman
Art Directors - Amy Pickwoad, Joelle Rumbelow
Standby Art Director - Nandie Narishkin
Assistant Art Director - Richard Hardy
Art Department Coordinator - Donna Shakesheff
Prop Master - Paul Smith
Prop Chargehand - Ian Griffin
Set Dresser - Jayne Davies
Prophand - Austin J. Curtis
Standby Props - Garry Dawson, Helen Atherton
Dressing Props - Mike Elkins, Paul Barnett, Rob Brandon
Graphic Designer - Chris Lees
Graphic Artist - Christina Tom
Storyboard Artist - Andrew Wildman
Petty Cash Buyer - Florence Tasker
Standby Carpenter - Will Pope
Standby Rigger - Bryan Griffiths
Practical Electricial - Christian Davies
Props Makers - Penny Howarth, Alan Hardy
Props Driver - Gareth Fox
Construction Manager - Terry Horle
Construction Chargehand - Dean Tucker
Scenic Artist - John Pinkerton
Assistant Costume Designer - Fraser Purfit
Costume Supervisor - Carly Griffith
Costume Assistants - Katarina Cappellazzi, Gemma Evans
Make-Up Artists - Sara Angharad, Vivienne Simpson, Allison Sing
Casting Associate - Alice Purser
Assistant Editor - Becky Trotman
VFX Editor - Joel Skinner
Dubbing Mixer - Tim Ricketts
ADR Editor - Matthew Cox
Dialogue Editor - Darran Clement
Sound Effects Editor - Paul Jefferies
Foley Editor - Jamie Talbutt
Graphics - Peter Anderson Studio
Additional VFX - BBC Wales Visual Effects
Online Editor - Geraint Pari Huws
Colourist - Mick Vincent

With thanks to
The BBC National Orchestra of Wales
Conducted and orchestrated by Ben Foster
Mixed by Jake Jackson
Recorded by Gerry O' Riordan

Original Theme Music - Ron Grainer
Casting Director - Andy Pryor CDG
Production Executive - Julie Scott
Post Production Supervisor - Nerys Davies
Production Accountant - Jeff Dunn
Sound Recordist - Deian Llyr Humphreys
Costume Designer - Howard Burden
Make-Up Designer - Barbara Southcott
Music - Murray Gold
Visual Effects - The Mill
Special Effects - Real SFX
Prosthetics - Millennium FX
Editor - Matthew Cannings
Production Designer - Michael Pickwoad
Director of Photography - Stephan Pehrsson
Script Producer - Denise Paul
Line Producer - Diana Barton

Executive Producers - Steven Moffat, Caroline Skinner

There’s something very odd about Mrs Gillyflower’s Sweetville mill, with its perfectly clean streets and beautiful people.

There’s something even stranger about the bodies washing up in the river, all bright red and waxy. When the Doctor and Clara go missing, it’s up to Vastra, Jenny and Strax to rescue them before they too fall victim to the Crimson Horror!

Madame Vastra and her partners, Jenny and Strax, investigate 'The Crimson Horror' - a mysterious condition leaving victims with red skin and preserved like statues - after discovering that one victim has the image of the Doctor visible in one of his eyes.

Investigations lead them to Sweetville, an idyllic community run by Mrs. Gillyflower and her never-seen "silent partner", Mr. Sweet, apparently as a home for the chosen few to help them survive the coming apocalypse. Jenny goes undercover as a convert and infiltrates Sweetville, where she discovers the Doctor, chained up in a cell, but only partially preserved due to the process not working due to him not being human; Gillyflower tends to dispose of such "rejects", but he has been saved by her blind daughter, Ada, who has become infatuated with who she describes as "my monster."

The Doctor is able to reverse the process on himself and he and Jenny go off in search of Clara, who has also been preserved (this confuses Jenny as she last saw Clara killed by the ice woman months earlier). The preservation process on Clara is successfully reversed, and Madame Vastra says the substance used to create the "Crimson Horror" effect is the poison of the red leech, a parasite the Silurians considered a major threat 65 million years ago. The Doctor and Clara confront Mrs. Gillyflower, who explains her plan and reveals that Mr. Sweet is in fact a red leech who has attached himself to her chest; their plan is to launch a rocket into the skies over England and spread the leech's poison over much of the planet. Ada, listening in, learns of her mother's plans and confronts her while Clara disables the rocket launch controls.

Holding a gun to her daughter's head, Gillyflower retreats into the rocket silo (disguised as a chimney) to activate a secondary launch control; she launches the rocket, but learns moments later that Vastra and Jenny have removed the poison payload. She decides to shoot the Doctor, but misses. Strax, who has climbed the chimney/silo from the outside, returns fire, causing Gillyflower to fall to the bottom of the silo.

As the old woman lay dying, Mr. Sweet abandons his host. Ada shares final words with her mother before killing the parasite with her cane.

Later, the Doctor returns Clara to her 21st century home, where she discovers that the two children she helps care for have discovered images of her and the Doctor in different points of time -- including a nuclear submarine in 1983 and a manor house in 1974. They also have found an image Clara does not recognize that is apparently of herself (but is in fact Clara Oswin Oswald). The children threaten to inform their father that their nanny is a time traveller unless she takes them in her time machine.

[Source: TARDIS Wiki]