In nineteenth-century Lombardy the Scacerni family own their own
floating mill on the
River Po, using the
watermill to grind crops harvested in the area. Berta Scacerni is engaged to Orbino Verginesi from a family of rural labourers. But following the
Unification of Italy they are now under the control of
Piedmontese authorities who rigorously enforce new taxes on the mills of the river. During a raid, to avoid being caught cheating the authorities, Berta's hot-headed brother Princivalle sets fire to mill causing damage. He serves a time in prison and, while the mill is repaired, Berta goes to work for Orbino's family on the land. Her relationship with Orbino becomes complicated by the ongoing battle between the landowners, led by the domineering Clapassòn who wishes to modernise his holdings, and the
socialist movement organising the labourers and
tenant farmers to demand better terms. The labour leader Raibolini calls a strike and the country people cease work. As the Scacerni refuse to stop milling the wheat, they are ostracised by their neighbours and Berta receives the hostility of her fiancée's family. Raibolini pressures him to break off his engagement with her but he refuses and considers
emigrating to America. The
Italian Army arrive to complete the harvest and a confrontation begins with the local woman. Many are arrested for assaulting the troops, before a deal is brokered to end the strike. However, in the heated atmosphere malicious gossip reaches Princivalle, recently released from prison, that Orbino has made love to his sister Berta multiple times and tiring of his fiancée, now wishes to abandon her. During a confrontation between the two Princivalle knocks down Orbino, killing him. == Cast ==