So are we getting Mardelys or not this season?
I figured that was what the buildup with their first two meetings was for, but who knows? If the battle is happening in episode 9, then either they need to meet the Manderlys, or else the Manderlys have been written out of the show... right?
In the books, the Manderlys knew where Rickon was, which wasn't a detail that came up in the show. Perhaps they shared the info with the Umbers in the background of the show's action, only for the Umbers to use that knowledge to get in good with Ramsay? And that's what will lead to the Manderly's renewed commitment to House Stark, in order to right their wrong?
#Speculation
Do we know who Sansa was writing to? Littlefinger?
That's what I figured, considering how she was acting as she wrote it. Or perhaps she was writing directly to Robin Arryn, and her look of concern was because she knows that he's unstable and doesn't know how he will react to her letter?