There are so many choices for saddest moment in Doctor Who. It sometimes catches me by surprise, because on the surface the show is a lot of fun. I’m sure to non-Whovians it looks like a show meant for kids that has cool aliens and time travel, etc. But a lot of the show’s themes are dark, frightening, or depressing. I always love seeing Sad Doctor because you realize the weight of everything he has to deal with. (I don’t love that he’s sad, of course. It just brings out the depth of his character and reminds you of all the terrible choices he’s had to make and how old he really is.)

Some candidates for saddest moment: Rose getting trapped in the parallel universe (this one would probably win except that things turn out okay for her in the end), Clara’s exit at the end of Season 9, and all the times that we see Sad Doctor.

For the saddest moment, I picked Donna’s exit from the show. Throughout her time as a companion, Donna grows so much as a person. She becomes more confident – no longer “just a temp.”

The Doctor also benefits from having her around. He needs her sense of compassion and empathy. They eventually become great friends, and it’s a refreshing change of pace to have no romantic undertones.

In a short summary that will be pretty much incomprehensible if you haven’t watched “The Stolen Earth”/”Journey’s End”, Donna receives energy from the Tenth Doctor’s hand which was being used to store excess regeneration energy. This creates a human version of the Doctor and also imparts Time Lord intelligence to Donna. The Doctor says the Time Lord consciousness can’t exist along with her human brain as it will kill her. Despite her protests, he wipes her memory. The Doctor always thinks he’s doing what’s best for people, but sometimes he gets it wrong.

Donna is now incapable of remembering anything about her time with the Doctor. If she does, her brain will overheat. This is the saddest moment for me because all of her character development is wiped away along with her memories. She will probably never reach the potential that we know exists.

Losing Donna hits the Doctor quite hard, and he travels without a companion for a long time. It’s usually not good for the Doctor to travel alone because he needs someone to keep him grounded. Donna was great at this, which is yet another reason her story is so sad.

What do you think is the saddest moment / saddest character story from Doctor Who?