Pssst, Nucky Thompson: turn around!

HBO has released a new poster in anticipation of Boardwalk Empire's September 25 return, one that makes it clear Steve Buscemi's main character will be in trouble on season two. Who might actually be behind him? Who will have Nucky in his/her sights?

There's always Rothstein... or Van Alden... or members of the KKK, as teased in this preview...