Workers building a shed brutally rape a young girl, and shortly afterwards they begin to be killed with a pneumatic hammer. That would be fine, but the killer, wearing camouflage, a motorcycle helmet covered with duct tape, and a yellow compressed air cylinder on his back, began killing everyone who crossed his path, regardless of gender or age. The sheriff and the doctor investigated the whole case, and only when the number of corpses exceeded ten did they have a brilliant idea about who could be involved in all these crimes…