Classic cult monster-movie horror. When a number of New Yorkers are brutally decapitated while sunbathing on their tenement building roof, two NYPD detectives are assigned to solve the case. Meanwhile, paranoid jewel thief Jimmy Quinn (Michael Moriarty) flees a botched heist and hides out on the roof of the Chrysler Building, where he unwittingly discovers the nest of the huge dragon-like creature that has been responsible for the deaths. As Quinn bargains with the police for a financial reward for his information about the creature's nest, a mysterious Aztec cult in the city start making human sacrifices to call on the creature they believe is Quetzalcoatl, the Plumed Serpent. Can the police get the location of the nest before more people are killed? And, once there, can they destroy the monstrous creature?