Two young men, Brandon and Phillip, share an intellectually superior worldview, leading them to embrace the concept of committing the "perfect murder"—one they deem to be an art form. Believing themselves to be intellectually superior to their peers, they strangle their former classmate, David, in their Manhattan apartment. They then audaciously hide his body in an antique wooden chest. The chest remains in plain sight as they host a dinner party, which serves as a macabre test of their perceived ingenuity. The guest list includes the victim’s father, aunt, friends, and fiancée, as well as their former prep school housemaster, Rupert Cadell. The thrill for the duo lies in the dangerous game of subtly referencing the crime among unaware company.

As the evening progresses, the thrill of their deed turns to tension. Brandon, the more dominant and daring of the two, relishes the challenge of dropping hints about their deed. However, Phillip grows increasingly anxious as he grapples with the moral weight of their crime and fears that they will be exposed. Cadell begins noticing oddities in behavior and conversation, his suspicions quietly mount. His inquiries and observations lead him closer to the truth, testing the limits of the murderers' carefully constructed façade. The party progresses against the backdrop of a stormy night in the city, casting an ominous mood over the supposedly cultured event and fueling the psychological cat-and-mouse game unfolding within the apartment walls.