A wealthy, possessive husband's investigation reignites his young wife's past love, leading them to plot against him. As obstacles fall away, their passion faces a new test.

The film shows how Italy's historic national hero Giuseppe Garibaldi (embodied by Renzo Ricci) leads a military campaign known as Expedition of the Thousand in 1860 and conquers Sicily and Naples. When the Bourbon monarchy has left Southern Italy, he supports Victor Emmanuel II of Italy who achieves a lasting unification under the aegis the House of Savoy. Roberto Rossellini has said he was prouder of this film than of any other film he ever made.