Tabitha, the cat of a wealthy elderly woman named Ella Venable, witnesses her owner's murder at the hands of her husband, Walter, and two accomplices seeking Ella's fortune. Ella’s body is buried in the woods, and the trio claims she went missing. Tabitha begins to act strangely, arousing fear and suspicion among the conspirators. Walter's niece, Beth, arrives at the mansion and grows wary as unusual events and the cat’s peculiar behavior unsettle the household.

Beth's curiosity and Tabitha’s actions lead her to discover cracks in the story told by her uncle and his accomplices. As Beth delves deeper into the mystery and Walter becomes increasingly paranoid, the cat seems to shadow their every move, appearing at inopportune moments and seemingly orchestrating eerie occurrences within the mansion. The growing tension drives a wedge between the conspirators as Beth inches closer to uncovering the truth about her aunt's disappearance. Their lives spiral out of control as they attempt to silence both Beth and the unnervingly omnipresent Tabitha, whose silent vigil keeps Ella’s memory alive.