Lots of sad things happen over the course of Doctor Who, but most of them pale in comparison to the fate of River Song. It is a long and twisted tale that spans several seasons of the show, and perhaps her biggest tragedy is that knowing how it all ends isn’t even the worst of it. Needless to say: spoilers abound. You’ve been warned.
(Oh, yeah, if you didn’t know, Brits call TV seasons “series” across the pond. I’ll use their nomenclature from now on in this article.)
River Song is introduced in the fourth series of Doctor Who, the final one executive-produced by Russell T. Davies. She is a main character in “Silence in the Library” and “Forest of the Dead,” a two-part arc about a planet-spanning library overrun by dangerous creatures that live in shadows. The episodes were written by Stephen Moffat, who would become show-runner with the next series. She is presented as a rogue archaeologist, taking people on a tour of the deserted planet. From the beginning, she is tragic. She and the Doctor have a history, only it hasn’t happened to him yet. She knows him well, he knows her not at all. Two time travelers, out of sync.
In the second episode of the arc, you learn the fate of Professor Song: she sacrifices herself to save the love of her life, and the Doctor must live with the knowledge that someone who will become closer to him than anyone else will eventually die to save him. River’s identity lives on as the caretaker of a virtual world on the universe’s largest hard drive, but it is hardly a comfort. One would think that a sacrifice as noble as hers would warrant a great deal of devotion and respect. Sadly, it does not.
River Song returns in “The Time of Angels,” this time as a thief of sorts. She defaces a rare object in order to get the attention of the Doctor, and they go on their second adventure. For the time being, things are light-hearted. There is no reason to worry about her fate, as that has already been established. It is revealed that she isn’t all she seems: she killed someone very important, though the identity of this person is not revealed. River calls her victim “the best man I’ve ever known.”
She doesn’t return again until the end of the series, in “The Pandorica Opens,” this time as an inmate in an intergalactic prison, locked away for the crime alluded to earlier. She is her usual chipper self, gleefully breaking out of prison to go on another adventure with the Doctor. She continues her role as a femme fatale, mesmerizing men and bringing them under her thrall. She is integral to solving the riddle of the Pandorica, a prison designed to lock away for all time the most dangerous being in existence. River rescues both the Doctor and Amy Pond from the Pandorica, risking her life and showing yet again she is willing to die for the Doctor. This time, however, he saves her. The Doctor reboots the entire universe, undoing a multitude of losses incurred over the course of the series, most notably those of Amy’s fiance, Rory, and her parents.
River returns almost immediately in the series six opener, “The Impossible Astronaut,” and its companion episode, “Day of the Moon.” Over the course of this arc, River witnesses the murder of the Doctor, then meets up with a version of him almost 200 years younger. She helps him fight an alien invasion, displaying incredible battle prowess. At the end of it, he returns her to prison. He offers to take her with him, and she refuses, insisting she must serve her time to fulfill a promise.
“A Good Man Goes to War,” the mid-series cliffhanger, is where things for River begin to really fall apart. The Doctor calls upon a number of favors he is owed in order to save Amy and her daughter, and River is the only one to refuse. She remains in prison as the Doctor takes on an army created to destroy him. Only when the entire event has unfolded does she appear to explain herself: she could not interfere with the rescue. Or, more specifically, the botching of the rescue.
Melody Pond, the baby in question, was kidnapped by a coalition bent on destroying the Doctor. They succeed in escaping the battle with the infant. The Doctor promises to find her, and River appears just in time to tell him how and reassure Amy that things will work out. She knows this, because she is Amy’s daughter.
This sounds all well and good, if a little unnerving, as River Song also becomes the Doctor’s wife. Don’t worry, though, because that rescue doesn’t happen, either. The Doctor doesn’t save River/Melody. In the next episode, “Let’s Kill Hitler,” Amy and Rory confront the Doctor on the whereabouts of their daughter, and he admits he has yet to find her. Over the course of the episode, it is made clear he never finds her, and that River/Melody has been brainwashed and programmed to kill the Doctor.
So, congrats all around on that one, right?
Melody is revealed to have regenerated and become Amy’s childhood friend, Mels, her best friend and the inspiration for the name of her child. The recursive Melody Pond regenerates again, this time into the form of River everyone knows and loves. She proceeds to begin attempting to kill the Doctor. She tries several times. She is very persistent.
So, we establish that everything River said about Melody being rescued in the last episode is a lie. She lived through the events already, and knows she’ll be programmed to kill the Doctor. In fact, she’s already done it in her own timeline, because she is serving time for it. She gives up her ability to regenerate in order to keep the Doctor alive after poisoning him. The Doctor states that it is too late to save her; they know too much. Amy and Rory give up on saving their daughter, because, hey, timey-wimey and all that.
River goes on to study archaeology, and is unable to escape her fate. She is recaptured by Madame Kovarian and The Silence at her graduation, and is sent to shoot the Doctor in the scene which unfolds in “The Impossible Astronaut.”
River attempts to stop herself, creating an alternate reality where the entirety of history occurs at once. The Doctor, being the cleverest thing in the universe, finds a way to cheat death by placing a robot decoy of himself at the scene. The Doctor marries River in the alternate universe and makes her promise to pull the trigger when the time comes, because it won’t be him that dies.
River serves her sentence to protect her love, while he galavants about space and time. The Doctor can reboot the universe more than once. He can create a pocket universe to bring his race back from extinction on little more than a whim. Clara can split herself into a thousand pieces across space and time. But River Song serves her sentence for helping the Doctor fake his own death. Oh, sure, the Doctor takes her out every night. At best, that makes River Song a kept woman. The one and only woman who ever one-ups the Doctor and calls him out on his bullshit doesn't even rate an attempt at freedom.