Georges Sarret (Michel Piccoli) is a French attorney with a gruesome plan to marry and murder innocent people and collect their hefty insurance policies. He approaches sisters Philomena (Romy Schneider) and Catherine Schmidt (Mascha Gomska) for help with his deadly scheme. Though the sisters are initially shy, they quickly warm up to the slyly clever Georges. As the trio marry and murder their victims and manipulate insurance companies, they become more and more sadistic. Featuring an original film score by legendary composer Ennio Morricone.