"Istanbul, 1926: After her historian father makes a clandestine journey abroad, Jane and the dapper Redvers trace his footsteps while signs of danger loom back home in the United States. They're greeted at their destination by Aunt Millie and unsettling news: Professor Wunderly was on a mission to locate the lost heart of Sultan Suleiman the Magnificent -- a legendary relic from the Ottoman Empire said to possess potent mystical powers -- when he...