Scouring the underbelly of Cleveland, Ohio, a priest figures out that Satan is the invisible force sucking the souls out of bodies. Upon further investigation, he learns that a baptized, newborn baby makes Satan visible for several minutes during which time he can be sent back to hell. The priest and his helpers try but after each failed attempt, they are made immobile as Satan gets in each one's face and, using mental telepathy, tries to convince them they're going to hell with him. A mysterious girl shows up and the priest learns that his arch enemy is not only her father but is also the leader of the cult responsible for bringing Satan to earth. He takes her to a safe place but the savage cult leader finds her, has her dismembered and fed to alligators for betraying him. At a meeting called by Satan, a virgin is sacrificed to the him after which he proceeds to kill two members he detected were turning to God. He informs the cult leader that he's been working on the priest and has him ready to surrender to the dark side. He gives the order to finish the job and even though the priest wakes up to find himself tied to a chair with a prostitute ready to go to work on him, he makes such a heartfelt plea for his virtue, she finds she can't be the one to take it from him. When the cult leader realizes that the priest is incorruptible, he tries torture but his henchman is stopped dead in his tracks by Saint Michael the Arch Angle. After seeing the miracle, one of the cult members turns from his evil ways. The priest and his helpers go into hiding where he discovers one of his helpers is the key to their victory but Satan has convinced her that because of her past, she's doomed to hell. She refuses to help. As the priest is praying, the Virgin Mary shows him the secret to success and together, he and the woman cause the Devil immense pain as they use the words from Genesis to stomp him out of existence. Satan returns to collect the souls of the cult members. The one who changed his ways out of fear believed the Devil would be powerless over him but the Devil reminds him you must love God with all your heart and soul and mind, then takes his soul to hell--promising God he'll be back.