(previews start on Oct. 29; opens on Nov. 16) Katori Hall, a politically astute playwright with a word-ravished style, unveils the second play of her Signature Theater residency. Based on a real case, the script concerns a group of Rwandan schoolgirls who see a vision of the Virgin Mary. Michael Greif directs a cast that includes Joaquina Kalukango, who starred in Ms. Hall's "Hurt Village," and T. Ryder Smith.