Let the speculation begin!
The latest promo poster for the 2013 Dragon Ball Z anime movie invites a whole lot of speculation. So, what do you do after you've defeated Buu? Well, apparently you take your Z Warriors into the "Battle of Gods!"
It's been stated that new movie will take place between Dragon Ball manga chapters 517 and 518, in the 10 year timeskip after Goku defeats Buu, before before the 28th World Martial Arts Tournament.