Based on real events, and set in Rio de Janeiro, A Wolf at the Door is the nerve-rattling tale of a kidnapped child and the terror of the parents left behind. When Sylvia discovers her six-year-old daughter has been picked up at school by an unknown woman, police summon her husband, Bernardo, to the station for questioning. From that point on, the film takes increasingly sinister turns as it delves into the events that led to the girl’s kidnapping. With plot twists that will keep the audience on the edge of their seats, A Wolf at the Door is a darkly disturbing journey into the extreme limits of the human capacity for obsession and revenge.

Adapted from his autobiography, the film recounts the story of Hiroito, The King of Boca do Lixo (a region in downtown São Paulo of the fifties where various nightclubs, strip joints, prostitution, bars, and drugs can be found). Hiroito was a well born bohemian and at the age of 21 was accused for the murder of his father, who was violently stabbed over 40 times with a razor. Hiroito was not charged, however two months after the death of his father, Hiroito bought two guns and moved to Boca do Lixo and became one of the most dangerous criminals of the region.

After a bloody invasion of the BOPE in the High-Security Penitentiary Bangu 1 in Rio de Janeiro to control a rebellion of interns, the Lieutenant-Colonel Roberto Nascimento and the second in command Captain André Matias are accused by the Human Right Aids member Diogo Fraga of execution of prisoners. Matias is transferred to the corrupted Military Police and Nascimento is exonerated from the BOPE by the Governor.

In 1997, before the visit of the pope to Rio de Janeiro, Captain Nascimento from BOPE (Special Police Operations Battalion) is assigned to eliminate the risks of the drug dealers in a dangerous slum nearby where the pope intends to be lodged.