River Song is getting ready to meet the Doctor for …
River Song is an archaeologist, time traveler, and adventurer whose connection to the Doctor is only revealed slowly over time. When we first meet her in “Silence in the Library”, she has known the Doctor for a long time, and though that adventure ends up being their last together from her perspective, it is only the beginning for the Doctor.
It is implied, over the course of her tenure, that River is the Doctor’s lover (and, if you count an alternate timeline ceremony, his wife) as well as the daughter of his longtime companions Amy Pond and Rory Williams. River and the Doctor, both being time travelers, never meet in the right order, so they rely on River’s TARDIS-blue diary to calibrate themselves and avoid “spoilers”.