Chicago, October 1932. The only ""beer"" allowed to be served during Prohibition is ""near-beer"" or ""Near-O""-- which is 0.5% alcohol, as opposed to real beer which is 4.0% alcohol. And so, a lot of legitimate beer producers wind up ""spiking"" the barrels of near-beer with pure alcohol, to get it up to strength. A northside brewer named Woody O'Mara wants to smash all his competition; he tells his girlfriend Amy Gratzner, a rather plain-looking 23-year-old secretary for rival brewer Franz Koenig, to blow the whistle on her boss.