Everyone is gearing up for Sunday’s return of Game of Thrones, and one of the joys of the show is that there are all sorts of fan theories that can help us guess where the show is going in its final two seasons. io9's latest video series examines the ones most likely to come into play in season seven. This first video looks at the legend of Azor Ahai, which could reveal who’s destined to destroy the White Walkers.