The atmosphere is bleak in New-München, this small village of Dakota founded by German settlers. The reason? A shortage of beer caused by the general strike that paralyzes all the breweries in the country! So when Lucky Luke is called to rescue, he will have to go to Milwaukee, the American capital of beer, to ease the tensions between Marxist trade unionists and industrial barons. And if our lonely cowboy is already overwhelmed by the dreads of the social conflict, it is without counting on the Daltons who come to meddle in the game...