Isabelle, a young tenure-track professor, tests the limits of free speech by encouraging her students to participate in an unmoderated discussion group. But the discussion board rapidly gets out of hand when an anonymous student posts offensive comments and videos, and Isabelle must decide whether to intervene or to let the social experiment play out. As the posts turn abusive and threatening, Isabelle and her unknown tormentor engage in a high-stakes game of cat-and-mouse that has Isabelle questioning her beliefs and fearing for her life.