The simultaneous joy of watching Doctor Who is that every episode is completely different and yet identical. Different, because each week the show reboots its basic setting, with a new supporting cast and even a radically different genre. Just in this current run of episodes, we've had a techno-thriller set in the present, a galactic showdown set on the cusp of an angry-demon superstar, a ticking-clock Alien riff onboard a Soviet submarine, and now a mid-70s haunted-mansion ghost story. But the Who machine has a pleasingly well-oiled, sui generis structure. The pre-credits scene introduces the new setting and a new cast of ace British actors; the first half of the episode establishes a fairly clear-cut story arc; and the second half of the episode usually winds up undermining that story arc, as monsters begin to seem less monstrous and minor actions have major cosmic reverberations. There are variations, of course. (A typical Steven Moffat will regularly undermine, deconstruct, and reboot its own story arc every five minutes or so.)
And then there are episodes like "Hide," which float along fairly directly, with one sudden radical shift that would be impossible on any other TV show. The hour began in a scary room in a scary house. Professor Alec Palmer -- glasses, stern, handsome -- announced the location (Caliburn House) and the date and time (November 25th, 1974, 11:04 PM.) His partner Emma -- quiet, a little sad, beautiful -- announced the mystical nature of their work. There were spirits inhabiting the house, and curious technology attempting to communicate with them. A bizarre event occurred: an ethereal figure appeared, lit up by the light from Palmer's camera. Then an even more bizarre event: The Doctor and Clara knocked on the door and declared themselves Ghostbusters.
The Doctor knew about Palmer's work. And not just the ghost stuff, either. He knew that Palmer was a member of the Baker Street Irregulars, a.k.a. the Special Operations Executive, a WWII espionage unit. He also knew Palmer was a talented water colorist. He referred to Emma as Palmer's "Companion," establishing a link between the professor and himself. (Palmer was played by Dougray Scott, who was almost Wolverine in X-Men and almost James Bond in Casino Royale; this episode seemed to thematically argue that he could've been the Doctor, too.) The Doctor also established that Emma was an empathic psychic who can "sense feelings," so basically Betazoid.
Then they got a rundown of the mansion's history. Caliburn House was only a few decades old, but the ghost in the house dated back centuries. She was mentioned in Saxon poetry, in fairy tales: "The Witch of the Well." There were photos and paintings of the ghost, always in the same position, always screaming. The Doctor went to go investigate the house. Clara came with him, after some coaxing. The Sonic Screwdriver helped him track down a curious corner of the house, where he drew a chalk circle. There was something moving in the shadows; the house began to get very cold; and there was a "very loud, angry noise." Clara told the Doctor that she wasn't scared and he didn't have to hold her hand, leading to the immortal horror-movie line: "I'm not holding your haaaaaAAAAAANNND!" It looked exactly like this:
In the main room, a shiny black mirror-thing suddenly appeared, floating in the air. In disappearing magic ink, the ghost had written a message: "HELP ME."
NEXT: Professor, profess thyself