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A murder investigation uncovers a plot that could destroy the world as we know it in this thriller. When a scientist doing research on nuclear weapons is murdered during a hospital stay, federal investigator Dave Pomeroy (Howard Duff) is called in to find out who killed him and why. With the help of Dr. Paula Stevens (Linda Cristal), the late scientist's assistant, Pomeroy learns that the scientist fell victim to a group of communist renegades whose members include two brilliant but unstable weapons experts, August Best (Nehemiah Persoff) and Myra Pryor (Anne Jeffreys). Pomeroy discovers that Best and Pryor have constructed an atomic bomb of their own -- and that they're threatening to use it to start World War III, forcing the detective to take swift action to prevent worldwide devastation. Panic in the City also features Dennis Hopper in the small role of Goff, just a year before Easy Rider would make him a star.