To really keep a secret... a great friendship is needed. Summer. An island in southern Italy. A world torn by modernity and regressive traditionalism, and the unwinding of three women’s lives. Despite the substantial differences that separate them, they are forced to unite for salvation. Gilda (Claudia Gerini), a genuine beauty coming from the continent, who practices the world’s oldest profession to make a living. Olivia (Cristiana Capotondi), the perfect wife in the prime of her youth, beauty and refinement, who arouses the other women’s envy thanks to her idyllic life and handsome husband. Crocetta (Sabrina Impacciatore), the ugly duckling that according to rumors brings bad luck to any ill-fated man who approaches her. A further complication to their lives is the arrival of police official Nico Malachia (Vinicio Marchioni), proud and abrupt in his manners.
He immediately understands that the three women are hiding a secret... A girlfriend’s guide to murder is an all-female movie that unveils the contradictions of the feminine character: strength and weakness, honesty and deceit, love and hate.
The story deals with a friendship between these three women, all so different and all so alike.