It tells the story of Dietrich von Bern and his heroes. The saga begins with an account of Dietrich's ancestors and youth. Then it tells how the heroes Hildebrand, Witig and Heime reach Dietrich's court at Bern. Competition is hot: both Heime and Witig challenge Dietrich to single combat. Heime loses, but Witig wins. In a fit of sulking Dietrich goes off to kill a dragon and find two more heroes.
When Dietrich has gathered ten heroes, he invites two of the Nibelungen, Hagen and Gunther, for a banquet. During this banquet, he announces his great plan: With his twelve heroes, he will travel to Bertangaland to challenge king Isung, his eleven sons and his standard-bearer: the great Siegfried. The heroes enthousiastically follow Dietrich's lead, but most of them lose their fight. Dietrich himself defeats Siegfried, who marries Grimhild, sister to Hagen and Gunther. Then, at the end of Dietrich's youth, his realm is attacked by his uncle Ermenrik, king of Rome. Dietrich flees to the court of Attila the Hun in Soest, where he will stay for some twenty years.
When Dietrich returns to Bern he is eagerly awaited, for king Ermenrik has died and his successor is not very loved. Dietrich even conquers Ermenrik's ancient kingdom: Rome. At the end of his life he becomes a Christian, sacks a monastery and fights his last fight. Dietrich wins this last fight, but is so sorely wounded that he dies on his way home.
King Arthur appears in passing as the father of Princess Hilde, whose hand in marriage is won by the Prince Herthgegn.