There is a summary of The Non-Existent Knight by Italo Calvino available directly through this link on eNotes. In addition to a complete summary of the story, you will find character analyses, theme information, and critical writings.
The summary information will assist you as you read the novella. At its outset, the story seems to be simple tale of “the non-existent knight,” Sir Agilulf, of Charlemagne’s army. As it progresses, the story is filled with twists and turns, and innuendo about the various characters and their “non-existent” lives. When Torrismund enters the tale, the knighthood of the “non-existent knight” comes into question. Torrismund declares he is the son of the woman, a supposed virgin, who Sir Agilulf saved. He was ultimately knighted for this act. From this point on, Calvino intertwines the stories of these characters, through both their intentional and unintentional actions in their quest to provide the truth about their claims.