On a recent Thursday, Chantal Smith, a creative director, met the actor Jon Hamm and the writer-producer John Mankiewicz outside Studio 525, in Chelsea, to give them a preview of the party space for the première of their new docudrama, “The Big Lie,” débuting the following night at the Tribeca Festival. Hamm wore aviator sunglasses, a brown denim jacket, and cuffed jeans; Mankiewicz wore a suit with no tie. They both looked intrigued. Smith gestured toward the entrance, which would be red-carpeted and ringed with lights. “It looks glamorous from the outside, but you’ll quickly discover that everything is not as it seems,” she said. “The Big Lie,” in which Hamm plays an F.B.I. agent, is set in McCarthy-era Hollywood, among blacklisted writers and directors struggling to shoot a workers’-rights-themed movie while being treated as political subversives. Hamm’s character, via suave duplicity, is trying to stop them.