As a serial killer stalks the city, Julia — a young actress who just moved to town with her husband — notices a mysterious stranger watching her from across the street.

In Paris, two workers find a hidden chamber while digging the underground of the Saint Jean André Church. They collect the valuable objects in the spot but they are attacked by a creature. Meanwhile, the discredited Professor Jack Randall, who wrote a book about Gargoyles rejected by the experts, is encouraged by his friend Carol Beckham to peek the place out. They sneak in the site during the night and while Carol is collecting some artifacts, Jack is recording with his camera. Out of the blue, Jack sees a winged monster coming towards him and he flees from the location with Carol, but breaks his camera. They go to a bar and a huge stone falls over his car. Jack takes a cab to his boarding house and Carol is attacked and beheaded by a Gargoyle at her apartment. On the next morning, Jack identifies Carol's body and becomes the prime suspect of Inspector Gibert of several murders. Jack decides to seek out the reporter of a sensationalist newspaper, Nicole Ricard, and gives his tape to her cameraman Walsh. When Walsh recovers the badly shaped footage, he shows Nicole and they realize that Jack is not crazy and he had seen a Gargoyle indeed in the underground of the church. They decide to return to the church to investigate.