For three seasons of Doctor Who, David Tennant's Tenth Doctor won Whovian hearts with his distinctive wit and depth as the most tortured Time Lord in the universe. This combination of humor and narrative complexity has made Ten one of the most beloved Doctors to date, and indeed, some of the most memorable Who storylines were conceived in this era.
Showrunner Russell T. Davies, along with writers like Davies's future successor Steven Moffat, helped create a world of intricate (sometimes quite intricate) and mindblowing plots. Here are the top ten Tenth Doctor episodes, ranked according to IMDb:
Human Nature (9.0)
The Doctor is not always a fan of his own longevity, but it's no surprise when mortal beings jump at the chance for immortality. In this first installment of a two-part story arc, the Doctor and his companion Martha (Freema Agyeman) insert themselves into an early-twentieth-century community to evade the Family of Blood, which wants to obtain the Doctor's Time Lord life span.
To prevent this, the Doctor becomes human and assumes the identity of a teacher named John Smith. Martha is perhaps the real hero in this story, as the Doctor essentially orders her to "invent a life story for me, find me a setting, and integrate me." Stuck with a Time Lord who doesn't know who he is and has no power? Pretty tough luck for a companion.
Midnight (9.1)
This one-off episode from season four follows the Tenth Doctor as he attempts to discover the source of terror on a shuttle traversing the planet Midnight. Written by Russell T. Davies, the episode is an instance of the oft-used format in Doctor Who: isolation in an enclosed space, with a group of strangers that the Doctor must persuade into following his lead. In this case, the strangers run into some slight trouble with, well, getting possessed.
As the crew members lose their calm, the Doctor doesn't always maintain his, either. "If we're going to get out of this, then you need me," Tennant's angry Ten exclaims at one point. Considering how irrational they all become, who can blame the Doctor for getting a little unhinged? Fun fact: guest-star Colin Morgan began playing the title character in BBC One's Merlin same year "Midnight" debuted.
The Stolen Earth (9.1)
In this penultimate episode of season four, the Tenth Doctor and Donna (Catherine Tate) are joined by a litany of past companions in their quest to save the planet and over a dozen others that have gone missing.
"The Stolen Earth" is actually a crossover episode between Who and its two majestic spin-offs, Torchwood and The Sarah Jane Adventures. As such, it boasts a tremendous cast that sees Rose (Billie Piper), Captain Jack (John Barrowman), Sarah Jane (Elisabeth Sladen), and Martha (Freema Agyeman) assisting the Doctor once more. In this episode and its second part, "Journey's End," the Doctor battles the Daleks, who are perhaps his most iconic enemy in the Whoniverse.
Family Of Blood (9.2)
In defense of the Family of Blood, who wouldn't want to live as long as a Time Lord? Unsurprisingly, the Doctor reigns victorious over the Family in this follow-up to "Human Nature," but not without some striking emotional revelations. "Family of Blood" features a heartbreaking speech from Martha when she says of the Doctor, "He's just everything to me, and he doesn't even look at me, but I don't care, because I love him to bits."
Considering all that Martha does to help the Doctor (especially when he doesn't even remember who he is), the moment is particularly devastating.
Journey's End (9.2)
How often do you get to see the Doctor regenerate into the same incarnation? That's (sort of) what transpires at the start of this season four finale, which constitutes a sufficiently emotional follow-up to "The Stolen Earth." The injured Doctor partially regenerates to get back in tiptop shape, and explains in a hallmark moment of wit, "Used the regeneration energy to heal myself, but as soon as I was done, I didn't need to change. I didn't want to. Why would I? Look at me."
This clever event is followed by the successful defeat of the Daleks, but also the tragic end of Donna's time as the Doctor's right-hand woman. In one of the most disturbing companion departures, her memory of the Doctor and all their escapades must be removed. Although season four was Tennant's last as the Doctor, he did not regenerate into Eleven in this episode; instead, a few standalone episodes were released over a year after season four, culminating in the "The End of Time."
The Girl In The Fireplace (9.3)
Past, present, and future collide in this wacky episode that invokes both space travel and corsets. After discovering a 51st-century spaceship in which he can see an 18th-century French girl through a fireplace, the Doctor must figure out what's so special about her -- and, of course, how to save the day.
The episode is a brilliant combination of the historical period pieces and futuristic space plots that Who executes so well.
Doomsday (9.3)
In the perpetually-traumatic finale to season two, the Doctor and Rose Tyler are separated indefinitely by the aftermath of a battle involving the Daleks and Cybermen. When one Cyberman says, "Together, we could upgrade the universe," you know it's going to be a tough battle!
Although Earth is saved, Rose and the Doctor end up stuck in two different universes. Much more than a wall separates them, but both gravitate toward the physical area in which Rose was pulled into the parallel universe. Tennant delivers an incredible performance, touching the wall with an eerily vacant look in his eye, but Billie Piper's delivery is even more affecting as she sobs uncontrollably in her new world. While Rose and the Doctor's reactions may differ, their trauma is most certainly equal.
Silence In The Library (9.4)
The enigma of River Song (Alex Kingston) and the Doctor begins ... and then ends, in a sense ... during the first installment of this two-part story arc, where viewers see the two meet. This is their first encounter from the Doctor's point of view, that is. As Whovians know, "first" is highly relative when dealing with the chaotic nature of relationships on Who, especially the inherently nonchronological saga of the Doctor and River Song.
The episode kicks off when Donna and the Doctor arrive at an unusually empty library, where they encounter the homicidal and shadowy Vashta Nerada. Alex Kingston's debut as River Song is a powerful one, as her sensitive reaction to the Doctor quickly convinces viewers that their relationship is terribly complex -- even if we have not seen any of it.
Forest Of The Dead (9.5)
The follow-up to "Silence in the Library" includes one of the most momentous moments in Who canon: River Song's death. It's a rare moment that becomes even more traumatizing when you progress through the show, because at this point, viewers had only seen River Song in one other episode. River's subsequent character development, including her relationship with not only Ten but Eleven, and Twelve, is one of the most complex and riveting Who storylines.
For one, River is later revealed to be the daughter of Amy and Rory Pond, two of Eleventh Doctor's principal companions. Only Doctor Who can kill off a character before you even know her, then develop her and make you swoon. Kind of similar to the Doctor's experience, huh?
Blink (9.8)
The persisting critical and audience acclaim for this haunting episode is no surprise, given that it introduced one of the most sinister villains in Who history: the Weeping Angels. Written by Steven Moffat and guest-starring Carey Mulligan, the story follows Mulligan's Sally Sparrow as she grapples with the "timey-wimey" effects of the Angels. The Weeping Angels have appeared in several Who episodes since, including a season seven episode that concluded Amy and Rory's time as companions to Eleven.