South Park’s Trey Parker and Matt Stone describe their Broadway Musical, The Book of Mormon, as an “atheist love letter to religion.” The show, which opens March 24, tells the story of two young missionaries who travel to a troubled area of Africa — beset by AIDS, poverty, a warlord who likes to force clitoridectomies, and just, overall, lots of despair — to spread their faith. We spoke with the pair at length about just why they love and are obsessed with Mormons, how Star Wars is a religion, and the future of South Park.