Italian horror maestro Mario Bava's influential body count stalk-and-slash template opens with a classic double murder (copied exactly by Friday the 13th Part 2) and then hurtles on in scream-lined fashion to kill each of the 13 candidates in line to gain a vast fortune in cash and property. Unreeling like a macabre joke, the shock ending has to be seen to be believed in Bava's part Elizabethan tragedy, part Tex Avery cartoon, ultra-violent carnage spectacular.

An elderly heiress is killed by her husband who wants control of her fortunes. What ensues is an all-out murder spree as relatives and friends attempt to reduce the inheritance playing field, complicated by some teenagers who decide to camp out in a dilapidated building on the estate.