The Blackwood residence is a menacing house, a citadel set apart from the conforming ire of its small, conservative Vermont town. Residing within that fortress of isolation are the teenage Mary Katherine “Merricat” Blackwood, her older agoraphobic sister, Constance, their wheelchair-bound uncle, Julian, and their doting cat, Jonas. Mary serves as the caretaker, only leaving the residence for a trip or two to the local grocery store.

Their parents, John and Ellen, Aunt Dorothy, and younger brother, Thomas, once lived there. It has been six years since their poisoning. Now, their pipe-smoking cousin, Charles, has paid them a visit, bringing with him an air of deceitful charm. Constance may have taken the bait, but Mary senses an alarming presence—one she can’t seem to expel. And the watchful eyes of the outside world are just a little too pleased with the outcome.