It is clear, in conversation, that Casey Affleck is still trying to work Company out. His third directorial feature, set to premiere next week at the Venice Film Festival, begins on Christmas Day circa 1975, when a young woman (Emily Alyn Lind) arrives at a party and begins telling a strange story to those in attendance. From there, Company proves as rich in atmosphere as it is in ambiguity, unfurling a Gothic-infused mystery across three different timelines that click into collective place only in the film’s final moments. “There’s the story you think you’re going to tell, and then there’s the one that comes out of you,” Affleck says….