Wynonna returns to her childhood home, which was once besieged by the ghosts of the outlaws Wyatt Earp slayed. It was there that the Revenants abducted and killed her eldest sister Willa, and where her father died (shot by Wynonna, who was trying to shoot the Revenants).
Dolls makes Wynonna a Special Deputy with the Black Badge Division (well, really, he forces her into it by threatening to arrest her for homicide if not). So their partnership is official. Unlike their attraction for each other, which is still on the down low.