Paul Steward is a disillusioned magazine editor living in New York City, grappling with an overwhelming sense of emptiness and despair. Despite outwardly living a successful life with a prosperous career and a family, Paul finds himself trapped in a loveless marriage with his wife, Miriam, who is burdened by her own mental struggles. Troubled by the monotony and perceived meaninglessness of his existence, Paul becomes consumed by the notion of orchestrating a horrific act that would bring a final end to his turmoil—he meticulously plans to kill his family and subsequently himself. This dark obsession grows as he imagines potential scenarios and outcomes while contemplating the motivations that drive him to such desperation.

Throughout the film, Paul's internal conflict unfolds as he interacts with those around him, including colleagues, casual acquaintances, and strangers, all while becoming increasingly detached from his surroundings. In a desperate attempt to find meaning or connection, he decides on meeting five prostitutes the night before his planned act; an experience that leaves him further contemplating life and its fleeting joys. As the day progresses, Paul grapples with moments of doubt and clarity, leading him to question the drastic path he has set for himself. His reflections highlight the broader themes of existential dread and the search for purpose amid life's struggles. These tense moments build up to an emotional climax, leaving the audience on edge about Paul's ultimate decision.