Chicago, 1930. At the height of Prohibition, Al Capone rules the city through illegal alcohol trafficking and a vast network of corruption. Tasked with bringing his operations to an end, Eliot Ness, a young federal agent with the Bureau of Prohibition, suffers an initial defeat against a seemingly untouchable criminal organization. Determined to continue his mission, he joins forces with veteran police officer Jim Malone, young George Stone, and accountant Oscar Wallace. Together, these incorruptible men set out to bring Capone down, despite the violence of his associates and the corruption spreading through the city's institutions.