A friend from the past asks for private investigator Lee Arnold's help in tracing his son: Fayyad al'Barri was last thought to be in Syria having embraced radical Islam. But a cryptic message has prompted his family to believe Fayyad has had a change of heart and is searching for a way back home. With fellow investigator Mumtaz Hakim's help, they might be able to establish contact. From the bright lights of the Western world, to shady boxing clubs and murky online jihadist recruitment, and while violence erupts close to home, Mumtaz and Lee are on an unknown path into the mind of a terrorist, journeying closer to danger than they ever imagined.