In the chaotic slums of Rio de Janeiro, the favelas are plagued by violent drug gangs and corrupt cops. Amidst this turmoil, an elite special police force unit known as BOPE (Batalhão de Operações Policiais Especiais) operates, tasked with tackling the most dangerous criminals and missions where the regular police force cannot cope. Captain Nascimento, a hardened veteran of BOPE, finds the intense brutality of his job conflicting with his growing desire to lead a safer life, as he and his wife are expecting their first child. As the Pope plans a visit to the city, Nascimento is pressured to squash the rampant crime near the Pope's route and to find his own replacement, leading to a frenetic search within the favelas to restore order.

Nascimento narrows down his search for a substitute to two promising police officers: Neto and Matias. Neto is a hot-headed, action-driven officer who yearns to make a difference but is frustrated by the systemic corruption in the police force. Matias, on the other hand, is an idealistic and intelligent rookie cop who is studying law and sees his police work as a form of community service. As they undergo BOPE's grueling training process, known for its rigor and mercilessness, both officers confront the moral dilemmas inherent in working for a squad that often operates above the law, facing the harsh realities of urban warfare and the blurred lines between right and wrong in their fight against Rio's underworld.