El Pacto (1976)

Following the death of their beloved mother, a brother and sister grow unnaturally close in the taboo erotic drama El Pacto (1976). Fernando Aliende and Ana Martin star as the sexually aroused siblings who react to the death of their mentally ill mother by pursuing an increasingly friendly relationship. When the couple crosses a line and begins exploring their more amorous desires, sister Teresa (Martin) drifts perilously close to succumbing to the insanity that gripped her mother. There’s little doubt that Martin’s performance here will drive male audiences good and crazy--the slender brunette shows an abundance of skin while keeping it in the family.