Renata Salazar, the wife of Juan Salazar, a successful wine farmer near Concepcion, Chile, and the manager of the vineyard, Jorge Martinez, are lovers. They plan to murder Juan and make it appear to be suicide.

Renata steals Juan's gun and bullets and gives then to Jorge who then shoots Juan one night on the vineyard premises and leaves the weapon in the dead man's hand. The police verdict is suicide.

Jorge and Renata agree to share Renata's inheritance as she believes that she's the sole beneficiary in Juan's will. But Juan leaves his estate to Renata and his son Pedro in equal shares.

Pedro doesn't believe that his father committed suicide and hires a female Mapuche private detective, Sayen Cayancura, to investigate his father's death. Before becoming a detective, Sayen had worked with her father on their vineyard until it was confiscated by the Augusto Pinochet military regime, and has a vast knowledge of grape and wine production.

When he finds out that Sayen has breached their confidentiality, Pedro cancels his contract with Sayen. Pedro obtains finance from an American financier Luke Gleeson and buys his mother's share of the vineyard.

Renata moves to Santiago and when Jorge Martinez resigns and leaves the vineyard to join Renata, Pedro in unable to find a suitable replacement other than Sayen, whom he refuses to employ. In an attempt to drive the vineyard into bankruptcy so that he can repossess it and sell it at a profit, Luke Gleeson hires two men to sabotage the wine production process.

Even though Pedro has cancelled his contract with Sayen, she decides to continue with her investigation. While in Santiago, Sayen comes across a photograph in the newspaper of Jorge and Renata stating that they're engaged to be married.

This provides Sayen with a possible motive for Juan's murder. She intensifies her investigation, but can she convert her discovery into evidence that will convict Renata and Jorge? And can the inexperienced Pedro prevent Gleeson's two thugs from destroying the vineyard?.