Realm, a virtual reality facility, is quite transparent about the erotic nature of its services: Wall to wall, it is lined with tempting previews of sexy, ready-made experiences. But Realm also offers something more: With the help of data-mining technology, clientele can create virtual facsimiles of real-life places and people. This hyper-personalization is what attracts Cecily, a young woman grappling with a disorienting world and an intense fixation.