What happens when a major theater production closes after just 16 performances? That’s the question investigated by the new documentary Best Worst Thing That Ever Could Have Happened, which will have its world premiere in the Special Events section of the 54th New York Film Festival. The film looks at Stephen Sondheim and Harold Prince’s legendary 1981 production of Merrily We Roll Along and its director, Lonny Price, was one of the young, unknown stars whose hopes were raised and dashed in the process. His documentary features never-before-seen footage of Prince and Sondheim at work, as in the clip above. Price and Sondheim will be at NYFF to present the film’s premiere.