During Napoleon's victorious campaign in Germany, the city of Kolberg gets isolated from the retreating Prussian forces. The population of Kolberg refuses to capitulate and organizes the resistance against the French army, which immediately submits the city to massive bombardments.

Aels, a rich and tempermental woman from the North, moves to Hamburg. She lives in a mansoin besides the newly married couple, Alrecht and Octavia. The friendship between Aels and Albrecht does not disturb the harmony of this marriage. But soon, Aels has a reoccurrence of a tropical disease, and because she is confined to bed, Albrecht rides by each day on his horse to her window and inquires as to her health. When, eventually, he gets sick with an epidemic, his wife takes over this dear service and greets Aels in her riding clothes, pretending to be Albrecht and comforting the sick woman, so as to not worry her about Albrecht also being sick. Aels, however, is not completely fooled and ends up dying of a broken heart. It turns out, she cannot live without Albrecht's love -something Albrecht only finds about from her last letter to him before her death.