Can someone break down what happened with Bolton, the Starks and the Grey Joys? My understanding is that:
Theon invades Winterfell, gets Bran to yield the city to him.
Theon is believed to have killed Bran and Rickon
Bolton's men arrive, get the Greyjoys to rat out Theon.
Bolton men take Theon hostage and sack the city, but tell Robb that it was the Greyjoys who sacked the city?
Don't forget that Ramsey mentioned flaying all the Ironborn who surrendered Winterfell in the letter he wrote to Balon.