A woman catches her husband cheating on her so she drugs him, castrates him and then keeps him chained up in the basement where he's forced to watch her have sex with other men before she kills them.

Eva, a sexology teacher, stays at Robertinho's farm to cure him of his sexual shyness. Successfully, she seduces him and his sister Naná, despite the uncompromising morality of their parents, who are from a traditional family in Minas Gerais. The father, after some resistance, reveals that his moralism comes from a childhood trauma when he caught his parents in a sexual relationship. Eva believes the father can benefit from her expertise and will try to cure him.