The story is derivative of Agatha Christie's 1939 novel, And Then There Were None (AKA Ten Little Niggers/Ten Little Indians), but the film is credited as being based on a screenplay by Mario di Nardo.
What is the plot of Five Dolls for an August Moon?
An industrialist invites his colleagues to his private island so they can exploit a resin formula invented by one of the guests, but a killer within the group disrupts the proceedings.