Sixteen-year-old Gwen, the newest and final member of the secret time-traveling Circle of Twelve, searches through history for the other time-travelers, aided by friend Lesley, James the ghost, Xemerius the gargoyle demon, and Gideon, the Diamond, whose fate seems bound with hers.
- ISBN: 9780805092660
- Author: Gier, Kerstin
- Translator: Bell, Anthea
- Published: 2012 , Henry Holt Books for Young Readers
- Themes: Family life, London, secret society, Time travel
- Descriptors: Europe, Fantasy, Germany, Young Adult (ages 14-18)
- No. of pages: 368