A husband hangs his wheelchair-bound ancient wife of wealth and is subsequently stabbed viciously. A developer, illegitimate son, and heiress(with her patsy husband who obeys her every command)all wish to secure the dead woman's land and bay for there's quite possibly a very lucrative tourist future in the area. Four young, horny adults make the mistake of stopping by the dead woman's empty home and fall prey to a killer spying on them. A neighboring couple who live nearby are against any development laying concrete over a place once dear to them(the husband, an avid bug collector, worries that it will disrupt his chances to collect any future insects..his wife, a supposed clairvoyant reads doom in her cards). The film shows the ongoing bloodshed committed by certain individuals who attack from behind so that they can gain the inheritance of prestigious land all to themselves.<br /><br />One killer uses a spade to tear open a beautiful Scandinavian woman's throat, shortly after burying that blade into a young man's face(..and subsequently pulling it out;a very impressive gruesome sequence that puts a lot of slashers to shame). A young couple having sex get sandwiched when the killer decides to place his spade away for a moment using a spear, thrusting it into the male's back through the unfortunate french chick on bottom..the spear kill in Friday the 13th Part 2 pales in comparison. One woman gets beheaded, one is stabbed in the stomach with a pair of scissors, there are nasty strangulations, and a shotgun blast that puts everything about the gain of wealth by any terms in perspective.<br /><br />The granddaddy of all slashers, this is Mario Bava unhinged letting loose his greedy characters to kill and maim. Nearly every last character is corrupt and dies. The ones who commit the final act of violence may prove that Bava was allowing this particular film to be so gratuitous as a means to poke fun at those loathsome heirs graveling for the scraps of their dying rich relatives.