EXCLUSIVE : Here’s an interesting one. Two-time Oscar nominee Felicity Jones ( The Theory of Everything ), coming off acclaimed drama Train Dreams , will play legendary author Agatha Christie alongside César winner Vincent Cassel ( La Haine ) in the noir mystery-thriller Eleven Missing Days , which Fortitude International will introduce to buyers at this week’s Cannes market. The movie is based on the true story of the British author’s mysterious disappearance. The synopsis reads: In December 1926, at the height of her fame, Agatha Christie became front-page news when she vanished in bizarre circumstances from her home. In a case of life imitating art, this whodunnit explores the investigation behind her disappearance, strangely resembling an Agatha Christie novel itself where everyone in her life became a suspect.…