A young woman makes a frantic 911 call about a brutal home invasion, which results in the shooting of her mother and father; as police interview her, they uncover a secret double life and an elaborate web of lies spun by a maniacal psychopath.

Police respond to a 911 call to find a father of two dead in his home with more than 15 gunshot wounds. Police question the family, but one person is missing: his mother-in-law. Now detectives must determine if this grandma could be a deadly psychopath.