Acting spouses Laurence Olivier and Vivien Leigh star in Alexander Korda's tragic tale of the adulterous love affair between Emma Lady Hamilton and Lord Horatio Nelson. The story begins in 1786, as the young and vivacious Emma Hart (Vivien Leigh) marries Sir William Hamilton (Alan Mowbray), the British ambassador to the court of Naples. Seven years pass and British naval hero Lord Horatio Nelson (Laurence Olivier) arrives at court to gain the king's assent in the war against Napoleon. Lady Emma and Lord Nelson fall in love. When they return to England, Emma and Nelson unashamedly begin to live together, although Nelson's wife refuses to divorce him. When the war takes a bad turn, Emma convinces Nelson to resume command and Nelson goes off to lead the victory at Trafalgar, where he is mortally wounded. After Nelson's death, Emma falls into depression and despair.