A devoted mother and housewife, Sylvia, goes about her day intending to pick up her daughter Clara from school, only to discover that Clara is missing. Her panic escalates when the teacher informs her that someone had called claiming to be Sylvia, stating that she was unwell and that a neighbor would come to collect Clara instead.
At the police station, Sylvia, along with her husband Bernardo and the teacher, are questioned to find any leads regarding Clara's abduction. During the inquiry, Bernardo suspicions rise as he reveals his affair with a woman named Rosa. Tension thickens when Rosa is brought in for questioning. Initially hesitant, she fabricates a story about being coerced into taking Clara by a mysterious woman named Bete, who supposedly had an affair with Sylvia's husband. However, the police quickly dismantle this ruse upon discovering no such woman exists, and under pressure, Rosa confesses everything.
The affair between Rosa and Bernardo sparked at a train station where Bernardo followed her after spotting her on the train. Their romance starts with a fiery passion, but things sour when Rosa uncovers that Bernardo had been dishonest about his marital status and family. Despite this betrayal, she decides to continue as his lover while also befriending Sylvia, posing as a mutual acquaintance and even giving gifts to Clara. Bernardo, upon learning of this, erupts into a furious confrontation with Rosa, demanding she never approach his family again. However, Rosa refuses to comply, attempting to tear apart their relationship by hiring a woman to pose as Sylvia's lover's angry wife, creating further chaos.
As their tumultuous relationship unfolds, Rosa confesses to Bernardo that her period is late. Following Bernardo's pressure, she takes a pregnancy test, which reveals she is indeed pregnant. Although she hopes for some form of reconciliation, she firmly declares her determination to keep the child, regardless of Bernardo's feelings. However, in a cruel twist, Bernardo tricks her into visiting a medical acquaintance who forcibly performs an abortion on her, leaving Rosa heartbroken and unstable.
In a dark turn of events, Rosa, desperate for closure, tries to meet Bernardo but finds herself rejected once again. In a moment of madness, she picks Clara up from school, leading her to an isolated area. There, she draws out a gun and tragically ends the young girl's life before proceeding to incinerate her body. The film concludes with a harrowing voiceover from a police officer, recounting Rosa's chilling statement: she exhibits no guilt or remorse for her actions, expressing a complete lack of concern for her fate or desire for forgiveness.
