While mystery surrounds the disappearance of some airplane in the Arctic, a monstrous, gigantic winged creature makes its appearance in the skies over North America. The Air Force does not make much of an association between the incredible presence and the inexplicable disappearances, and prepares a emergency plan immediately, but the horrible creature makes a joke of the efforts to hunt it down and destroy it. The monster, in truth, is immune to the weapons of the military, thanks to a shield of antimatter screen that surrounds it. The only possibility to take down the creature is to smash the shield that protects it. In record time, a deadly ray is created, and when and during a brief pause, while the monster has perched itself on Empire State Building, the beam is focused fully on it, killing it.

The best things of the film are the obvious. The feathered monster (without a head?) breaks up skyscrapers with its claws and drives away combat aircraft with its powerful wings is, in truth, on the screen a shabby, grotesque and ugly bird that brings to mind the paper machie nightmares of the worst Mexican or Japanese films. And the tension needed to nail the spectator [to the seat] is reduced by the sight of three actors that in science fiction had to force themselves to be frightened by the feathered, animal protagonist.

Known also by the title "The Mark of the Claw".