It tells how Sir Daniel, heir to the kingdom of Blumenthal, becomes a Knight of the Round Table and engages in fantastic adventures to defend King Arthur's land from an enemy ruler.
The herald demands Arthur swear immediate fealty to Matur, explaining that his country is defended by the contrivances of an inventor who has created a mobile palace carried by war elephants, invincible giants (of whom he is one), and a mechanical dragon whose scream is so intolerable that it makes even the staunchest fighting men cover their ears, rendering them useless.
These include rescuing a damsel from the attentions of an evil dwarf, after himself being saved by another noble lady from a magic net, and overcoming a horde of monsters without bellies.
The spirit of the heroic epic pervades Daniel, in contrast to other courtly Arthurian romances: Daniel's prestige comes from his abilities as a fighter, rather than his exemplification of courtly ideals, the pre-courtly focus on the importance of vassal-monarch relations prevails throughout the story, and Arthur takes part in the hostilities, contrary to his depiction as a roi fainéant in other romances.
The Prussian family von Blumenthal fancifully claimed a connection to the hero of this romance, and in the Late Middle Ages one or two of its members were christened Daniel.