Katie hasn't been herself since losing Nonnie, the woman who raised her. Isolated in their house, she shuts out everyone-including Justin, her longtime confidant from foster care. At Emily's urging, she searches for family and discovers a half-brother, Mark. His warmth draws her in, and she begins to hope for real connection. But when Katie uncovers unsettling lies, she cuts him off-only for Mark to keep appearing, acting like the perfect brother while pushing deeper into her life. His calm explanations erode her certainty, leaving her doubting her instincts and her own sanity. Convinced she's being watched, Katie spirals into paranoia, driving a wedge between her and Emily. Desperate, she turns to Justin, but their strained bond begins to crack. As everything unravels, Katie is forced to face the truth-and the cost of pushing love away.