I just watched the 2015 Christmas special The Husbands of River Song and I was wondering what part of River's timeline that was.
My theory is that this episode is set between her encounters with the 10th and 11th Doctors. I've also done a little digging on her screwdriver (left: The Husbands of River Song; right: Silence in the Library).
For River, this occurs between The Angels Take Manhattan and Silence in the Library.
In Forest of the Dead, River tells the Doctor about her previous encounter with him. Quoting directly:
The last time I saw you – the real you, the future you, I mean – you turned up on my doorstep with a new haircut and a suit. You took me to Darillium to see the Singing Towers. What a night that was. The towers sang and you cried. You wouldn't tell me why, but I suppose you knew it was time. My time. Time to come to the Library. You even gave me your screwdriver. That should have been a clue.
All of which matches nicely with the end of this episode. So unless they visit Darillium twice, her next meeting with the Doctor is in the Library.
This is alluded to during the episode – she’s getting close to the end of her diary.
And as @tilley31 points out in the comments, when the blue alien is reading her diary, he says:
The Pandorica opens. That sounds exciting. And goodness me, a picnic at Asgard. Some people really know how to snack, eh? The crash of the Byzantium – didn’t they make a movie of that? Oh, Jim the Fish – well, we all know Jim the Fish. And you’ve just been to Manhattan.
The last line is a reference to the episode The Angels take Manhattan.
(The only Manhattan-based episode I remembered was Daleks in Manhattan, which occurs before River Song has been introduced.)
[This section was heavily revised after I slept on it for a few hours. See the edit history for the original version.]
Could we see her again? Maybe, but it would need to be a bit special.
In this episode, she believes that the Doctor is limited to the standard 13 incarnations, and isn’t aware of Peter Capaldi’s Doctor. Since she goes directly to the Library, there’s nowhere in her timeline for him (or a later Doctor) to meet her without her realising that there are more Doctors.
(They could do another episode in which, as this episode starts, River is completely unaware of who the Doctor really is, but that might be hard to pull off more than once.)
The Guardian’s review recounts Steven Moffat at last week’s BFI screening, when asked whether Alex Kingston would reprise her role as River Song. He’s keeping his options open:
I killed her off in her first adventure, I wrote her as a ghost in another adventure, I wrote some minisodes for a DVD which were definitely her last appearance. There is no way to kill off River, she started dead!
If you consider the (Capaldi) Doctor not being able too tell River exactly what would happen but in general knowing that in the Library River sacrificed herself and he used the cop embedded in her Sonic to preserve her consciousness - many would argue that this is not truly River but just an echo of her (as they even say regarding the chips and data ghosts during the Library story). But at the same time, we and the Doctor see River(and her grave!) on Trenzalore and this is definitely post-Library from even River's point of view. My take on this is that the Doctor could have souped up or enhanced the chip in River's Sonic to be far more powerful than the regular ones, I'd be surprised if he didn't given what was at stake. For that matter, even River could have tweaked it to work far better or heck, it could even be a far better gadget disguised to look like one of the data ghost chips, as River almost certainly would have found it in her Sonic and discovered what it was even if she didn't know already, she is curious and highly intelligent and definitely knows that Sonic inside and out by the Library even instructing the 10th Doctor how to do things his Sonic can't. Since Trenzalore River was obviously out of the Library main frame and somehow using Clara to appear, and even apparently built or had manipulated her own grave to assist the Doctor, my take is she not only survived the Library but added a few tricks to her existence and ability to move around time and space without requiring a TARDIS. in fact, I fully believe River is still going strong, out there having adventures and fun we can scarce imagine. And she always will. :-)
