The Phantom Stranger teases the tale about to unfold. Jim Colter has come to the tiny island of Costa Roja, to film the sacred "Dance of the Serpent". Colter returns to his hotel room to find it ransacked. A man enters Colter's room, begging for help. This man offers to give Colter information regarding the Cult of the Serpent, in exchange for safe haven. Spying the Skull of the Serpent suspended from the ceiling fan in Colter's room, the man runs from the room in terror. The man hides away, in an abandoned shack, only to fall prey to the Curse of the Serpent.
Dining with his secretary, Theresa, Colter encounters the man again, as Colter's waiter. The man has clearly undergone some kind of mental trauma. Colter threatens to beat information out of the man, when his hand is stayed by the Phantom Stranger. The Phantom Stranger advises Colter to abandon his course of action. Colter refuses to be scared away. Theresa pleads with Colter to leave Costa Roja. Colter refuses, then rents a jeep to take him into the jungle. Colter's jeep trips a booby trap, that disables the vehicle, nearly killing Colter in the process.
The Phantom Stranger intervenes, again warning Colter not to proceed. Colter makes his way through the dense underbrush, following the sounds of drums and faint chanting. In a clearing, Colter spies the Cult of The Serpent. Colter begins filming their rituals. A woman steps forward, and begins the Dance of the Serpent. Venomous snakes slither up her form, winding themselves around her limbs. Writhing about in front of the flames, the woman removes her headpiece, revealing herself to be Theresa. In his surprise, Colter drops his camera. The sound of the camera striking the Earth disrupts the ceremony.
The snakes strike, killing Theresa. The Cult of the Serpent goes after Colter. The Phantom Stranger intervenes, and gets Colter to safety. The Phantom Stranger takes his leave of Colter, knowing that Colter's fate is set. Driving to the airport, Colter sees a mass of snakes in the road. The snakes wind about each other, transforming into Theresa. Colter swerves to avoid Theresa, crashing into a telephone pole. In a daze, Colter believes the car is surrounded by snakes. Attempting to escape the car, Colter is electrocuted by the high voltage wires... not snakes... spread out over the vehicle. The Phantom Stranger recovers Colter's camera, and exposes all the film.
Rachel Adams visits her husband's grave. Adams vows to find, and destroy, her husband's murderer, Frankenstein's monster. Mammon abducts Adams. Frankenstein's monster exhumes the body of Victor Adams, with the intent of resurrecting him. Mammon brings Adams to Mordecai. Adams is to be sacrificed to Mordecai's master, Satan, to allow Mordecai safe passage into Hell. Thinking it abandoned, Frankenstein's monster enters Mordecai's house. Hearing voices, Frankenstein's monster investigates. Seeing Adams imperiled, Frankenstein's monster does battle with Mammon.
Frankenstein's monster purposely loses the fight, so that he may be sacrificed in Adams' stead. At the last moment, Frankenstein's monster breaks his bonds. To save Mordecai, Mammon sacrifices himself. It's too late, though, and both men burn to death in the fires of Hell. Frankenstein's monster departs, to gather the equipment necessary to resurrect Victor Adams. Rachel Adams awakens to find the corpse of her husband lying at her feet. Adams screams.