John Shum leads an expedition to an supposedly deserted island only to find out that it's inhabited by a group of seriously demented characters,lead by Peter Chan Lung.This is a family that stays together,slays together and when the youngest one is refused in marriage to one of the young girls of the troupe they turn into savage maniacs.

Three lazybones friends manufacture a firebomb and place it in a cinema. Pearl, a sadistic young girl, has observed the scene, follows the bombers and starts to manipulate them. The four criminals plan more and more daring acts.