With James Wan's The Conjuring sweeping (and spooking) all before it at the US box office and UK filmgoers getting a serious frightening from this Friday, Empire's curiosity has been piqued. What makes a $20m film recoup its budget in less than a weekend and go onto make nearly $100m in less than a fortnight? Is it a talented director with a track record in low-budget, high-concept filmmaking? Good old-fashioned storytelling? A seasoned cast selling the scares? Then we realised: it's witchcraft! So we went along to the film's press junket in San Francisco to burn everyone involved.