I’m blanking on it, mainly because I did not like the River Song character at all. I can’t remember them being childhood friends. That “Hello Sweetie” was so grating.
You could have just said “Spoilers!” ;-)
The River Song character was one reason I quit watching the series, but I’m not a great scifi fan-what happened to her, anyway?
I do like “Battlestar Galactica” and “Star Trek” in all its incarnations, but that is pretty much it for the scifi...