A mysterious letter detailing a supposed Islamist plot to take over schools shocked Britain in 2014. But who wrote it? From Serial Productions and The New York Times, “The Trojan Horse Affair,” an investigation that became bigger than we ever imagined. All eight parts are available now, wherever you get your podcasts. To get full access to this show, and to other Serial Productions and NewYork Times podcasts on Apple Podcasts and Spotify, subscribe atnytimes.com/podcasts.

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