The year is 1453, and 17-year-old Luca has been thrown out of his religious order after proving that a holy relic is a fake, using his knowledge of Moorish science. Cast as a heretic, he is taken to the Vatican in Rome where he expects to be punished or executed. Instead he is recruited into a secret order investigating strange occurrences across Europe - The Order of the Dragon. Luca is sent to investigate an abbey where the nuns are showing signs of the stigmata and the abbess is accused of witchcraft. The abbess, Isolde, is actually a 17-year-old girl who has been shut up in the nunnery by her brother after her father's death, ensuring that she is unable to inherit any of the family's estate. Under threat of the pyre, Isolde manages to escape the abbey with her servant-girl, Ishraq, though no one can work out how she did it. Ages 13+.