Since, as you said, this is based of another book that would make it fanfiction, which means it should go in the fan fiction subforum. If you're having a problem with a plot point, or research you can ask for help here but the main forum is more about the process of writing itself. Actually work (finished or unfinished) belongs in the appropriate subforum.
There's no need to make another one there though, a mod can move this thread there for you if you post a link in the Elmo sticky (which I think is no longer the Elmo sticky, so I'll go check on that).