Older, crankier and infinitely more Scottish than those who came before him, Capaldi's Doctor was somewhat of a departure for the rebooted Doctor Who, which started trending toward younger, sexier versions of the heroic Time Lord after returning to TV in 2005. While it is true Capaldi's era was often unfairly saddled with writing that didn't always befit the actor's talents, that is a problem that does not lie at his feet, as he was always worth watching. He lent a sense of gravitas to the Doctor while still maintaining the role's necessary sense of childlike wonder.
Unfortunately, Capaldi's time in the TARDIS is coming to an end. The actor is departing the series at the end of Season 10 alongside showrunner Steven Moffat and co-star Michelle Gomez. But the question remains: Will the Doctor regenerate during the Christmas special as expected or will the long-running sci-fi series surprise us all by having him regenerate in the finale on Saturday? We don't have a time machine so we'll just have to wait and see; but until then, let's remember the good times and back at some of the best episodes from the Capaldi era.
10. "Last Christmas" (2014 Christmas Special)
Capaldi's first Christmas special, which featured a dream-within-a-dream-within-a-dream scenario thanks to some weird dream crabs, wasn't so much cheerful as it was creepy and uncomfortable. With the Doctor and Clara (Jenna Coleman) on the outs after Danny's death in the Season 8 finale, "Last Christmas" was frequently unsettling. But the decision to employ Santa (Nick Frost) gave the episode a jolt of whimsy and sense of humor. In the end, once the Doctor and Clara experienced the Darkest Timeline, the two quickly made up, thus putting a bow on Capaldi's first season as the Doctor.
9. "The Pilot" (Season 10, Episode 1)
Bill's (Pearl Mackie) introduction was also the first new episode of Doctor Who after more than a year off the air, and it was as delightful as it was comfortingly familiar. While most of the best episodes from the Capaldi era carry with them a sense of gravitas, "The Pilot" was a little lighter and a little brighter as it went through the familiar motions of introducing a new companion. We'll never tire of watching the Doctor's face light up at the prospect of sharing all of time and space with someone new just like we'll never tire of watching Bill ask the Doctor all the ridiculous questions we've been dying to ask for years.
8. "The Woman Who Lived" (Season 9, Episode 6)
The second half of a two-parter, "The Woman Who Lived" served as a harsh reminder of the dark side of living forever by exploring what happened to Ashildr (Maisie Williams) years and years after being turned immortal, then abandoned by the Doctor in the previous episode. She was the human incarnation of the Doctor's own worst fears, and the thrust of the hour served as a reminder to the Doctor about why he should never travel alone. Sometimes we need help remembering that Doctor Who can't be all fun and games, and "The Woman Who Lived" served that purpose successfully.
7. "Face the Raven" (Season 9, Episode 10)
"Face the Raven" will be remembered as the episode where Clara died, because she recklessly took on a death sentence that didn't belong to her in order to save someone else's life. It will also be remembered for being a bit of a fake out, since Clara is not actually dead: she's still running both toward and away from Gallifrey thanks to the Doctor's own inability to let her die in that alley. But it should also be remembered for being a really good, emotionally affecting episode that was the culmination of a season spent ruminating on death and how it is a natural part of existence.
6. "The Zygon Inversion" (Season 9, Episode 8)
More so than the David Tennant and Matt Smith years, the Capaldi era was characterized by a darkness that manifested itself as deeper discussions of universal themes and fears. "The Zygon Inversion" was the perfect example of this phenomenon and culminated with one of Capaldi's most emotionally affecting performances to date. The episode, which was the conclusion to a two-part Zygon invasion storyline, saw the Doctor give an angry, impassioned speech about the horrors of war; while the reveal that it never really mattered if the Doctor's friend Osgood was Osgood, or a Zygon pretending to be Osgood, put the episode over the top.
5. "Dark Water" (Season 8, Episode 11)
"Dark Water" was the culmination of a season-long arc teasing the Master's return -- this time as the female Missy (Gomez), short for Mistress -- and the reveal that the Doctor's oldest (and craziest) friend-turned-enemy was back made for one of the few truly shocking moments of the Capaldi era. Although Missy's mere presence in the Doctor's orbit eventually overshadowed her diabolical plan -- which centered on implanting the minds of the deceased into the bodies of Cybermen -- "Dark Water" was the kind of thrilling adventure the show (in recent years) only delivers every once in a great while.
4. "World Enough and Time" (Season 10, Episode 11)
Although the shock of the Master ripping off his disguise was dulled a little by the fact that John Simm's return to the series was announced prior to the start of Season 10, "World Enough and Time" was still one of the best episodes of Capaldi's run. It brought dramatic stakes back to the series by placing Bill in harm's way and then following through with the threat of turning her into a Mondasian Cyberman. It was a bold risk that ultimately paid off. And OK, fine: we also just really loved seeing Missy and the Master in the same room.
3. "Hell Bent" (Season 9, Episode 12)
The Season 9 finale was a relatively quiet and personal episode of Doctor Who that put the Doctor/companion relationship front and center and allowed the Doctor to reflect on what Clara had meant to him. Although there are issues with the fact the Doctor was willing to fracture time itself to save his best friend, the hour was also a welcome change from the bigger-is-better mentality of the Matt Smith era; and the intimacy of the situation gave Clara the proper (and more emotional) goodbye she deserved.
2. "Listen" (Season 8, Episode 4)
An instant classic, "Listen" had all the hallmarks of a Moffat-penned episode. It played with the concept of time being non-linear by visiting the past, present, and futures of multiple characters, which made the show's use of time travel compelling in a way it rarely is anymore. The hour also explored the universal nature of fear, one of the show's most basic components, in a creepy but relatable story that gave us a glimpse into what motivates and drives the Doctor. Meanwhile, the ambiguous ending showing that whether or not a monster even exists doesn't matter inspired further discussion even after the credits rolled.
1. "Heaven Sent" (Season 9, Episode 11)
"Heaven Sent," the penultimate episode of Season 9, was not just the finest hour of the Capaldi era, but also Capaldi's finest hour on the show. It was an ambitious and daring departure for the series that played with structure -- a closed energy loop meant the Doctor repeated the same motions day after day for millions of years -- and almost exclusively featured Capaldi acting opposite nothing but the walls of a prison meant to contain the Doctor. This was Capaldi's showcase, in other words, and it's unforgettable.
Doctor Who's Season 10 finale airs Saturday, July 1 at 8:30/7:30c on BBC America.