Up in the north, Robb has called the banners so all his bannermen have been coming to Winterfell. ("Bannermen" refers to the minor or smaller houses that have sworn loyalty to House Stark.)
Bran watches the army come in and then goes to the godswood to pray. (The giant servant Hodor carries Bran; and his wolf, Summer, makes people think twice before making jokes about Bran.)
Robb seems lordlier to Bran; he's even been able to assert his authority over bigger and older people, although once his wolf did have to bite off some fingers to do so. (These fingers belonged to Greatjon Umber. And after Grey Wind bit them off, Greatjon totally became Robb's biggest fan.)
The wildling woman Osha comes to join Bran in the godswood and she tells him that Robb is marching the wrong way: the real fight is with the Others in the north.
But at the end of the chapter, Robb moves his army south to fight the Lannisters.