In 2015, 23-year-old Hannah Mossman Moore was rubbing elbows with the fashion elite at London Fashion Week, courtesy of her internship at the buzzy jewelry start-up Alighieri. She struck up a friendship with an older man named “Kin,” an industry insider who began inviting her on glamorous trips around the world. Things took a turn when Hannah began receiving odd messages from “hackers” using Kin’s email. They also sent strange packages to Hannah’s home, impersonated her family members, threatened her, contacted old employers, and more. After almost 10 years of this mysterious harassment, Hannah and her “ex-stepmother”—the investigative journalist Carole Cadwalladr—take up the investigation themselves, with one goal in mind: to find the true identity of her cyberstalker. —Paulina Prosnitz