Cas, an ordinary 14-year-old, begins to experience something strange—a voice inside her head, shadows that seem to follow her, and an unsettling feeling that her life is no longer her own. As she struggles to make sense of the mysterious presence taking over her mind, her life becomes entangled with Elm, a highly disciplined, perfectionist artist whose only goal is to remain in control. Their rivalry, filled with tension and subtle admiration, pulls them into a deeper mystery. As the line between reality and the unknown blurs, Cas and Elm must navigate their growing connection while confronting the forces that seem to bind them.