Maybe he just felt, you know, he wanted to clear his head a bit

Pennsylvania, 1956. Frank Sheeran, a war veteran of Irish origin who works as a truck driver, accidentally meets mobster Russell Bufalino. Once Frank becomes his trusted man, Bufalino sends him to Chicago with the task of helping Jimmy Hoffa, a powerful union leader related to organized crime, with whom Frank will maintain a close friendship for nearly twenty years.