10 Years Ago, The Best Episode Of Doctor Who Redefined What The Show Could Be

On November 28, 2015, "Doctor Who" delivered a masterpiece it's been unable to surpass since. The penultimate episode of the show's season 9, "Heaven Sent," puts the Twelfth Doctor (Peter Capaldi) in a predicament that's unique even by the show's standards. Waking up in a mysterious glass chamber inside a huge, abandoned castle, the Time Lord has to navigate the vast compound in search of clues that might reveal the nature of his predicament. However, he's not alone: A large, cloaked figure (Jami Reid-Quarrell) is chasing him, and he can only temporarily halt it by offering secret truths about himself. Oh, and if all of this wasn't bad enough, it increasingly starts to seem that he's been here many times before, and that the clues he keeps finding may just have been left by himself. 

Directed by Rachel Talalay and written by showrunner (and simultaneously the best and most hated "Doctor Who" writer) Steven Moffat, the episode is technically the first half of a two-parter with the considerably less impressive "Hell Bent." For all intents and purposes, however, it's a big, bold bottle episode — a concept the show has always excelled at, with the likes of "Blink" and "Midnight" making regular appearances on lists of best "Doctor Who" episodes ever. However, "Heaven Sent" takes the theme above and beyond by stripping the Doctor of his TARDIS, companions, gadgets, and all other amenities. The end result is a thrilling hour of television that shows who the Doctor truly is when no one is looking ... and a one-man show for the ages.

Without going into full details about the plot's myriad twists, "Heaven Sent" is an exploration of the Doctor (or this version of the Doctor, anyway) when his back is well and truly against the wall. Capaldi's Twelfth Doctor is invariably less prone to hijinks and general wackiness than many of the other regenerations, but here, he has no need for even slight pretenses. There's no one around to impress — only a mystery to solve and a trap to escape. He becomes a raw nerve, exploring, deducing and fearing for his life ... but never once even considering to quit. When the full magnitude of the situation unfolds, he doesn't flinch despite the fright, pain, and overwhelming odds. He merely perseveres, finding a way to do what he has to regardless of the time needed and the personal cost accrued. 

All of this wouldn't work without Capaldi, of course. Few actors have what it takes to carry an episode like this entirely on their own back, and any other "Doctor Who" star — all excellent actors in their own right — would have struggled to nail the sheer presence the episode requires from its centerpiece. For my money, Capaldi has the greatest dramatic chops out of all modern "Doctor Who" actors. His wealth of talent is in full display here, as the Doctor slowly learns more and more about his predicament and painstakingly puts the hardest plan he's ever executed in motion. From quiet, tense moments to a mighty recital of the Brothers Grimm fairytale "The Shepherd Boy," Capaldi spends the entire episode at the absolute top of his game, commanding attention and elevating "Heaven Sent" above and beyond pretty much anything else "Doctor Who" has to offer.