This is a book for younger audiences and, from what I can tell, a novelization of stories narrated on the BBC (I think?). The book has gorgeous illustrations, is about 80 pages and does change events to make it more coherent and more focused on Morgana. It is basically Malory's story (with a lot of cuts, of course) from Morgana's point of view, which made it an extremely enjoyable (if short) book.
We follow Morgana's hatred for Arthur, her magic (with her friend Vivian), the way she manipulates her sister Morgause (using her love for her children, especially for Gareth)- all taking some of those Maloryian events (like the hunt for the white hart, or mixing the manipulation of Morgause into sleeping with Arthur, with the need to distract Arthur to steal Excalibur) to make the events more coherent (and shorter).