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. Subscribe today at nytimes.com/podcasts or on Apple Podcasts and Spotify. You can also subscribe via your favorite podcast app here https://www.nytimes.com/activate-access/audio?source=podcatcher. For more podcasts and narrated articles, download The New York Times app at nytimes.com/app. To find out about new shows from Serial Productions, and get a look behind the scenes, sign up for our newsletter at nytimes.com/serialnewsletter. Have a story pitch, a tip, or feedback on our shows? Email us at serialshows@nytimes.com