I've been reading about derivative works and general copyright, but I'm struggling to understand the scope of what is a derivative work.
Allow me to present my situation.
I have written a concept album, it is a retelling of a story previously told in a movie, let's say Robocop.
At no point is the film tile Robocop referenced, the song titles and plot points are designed to be familiar to fans of the movie. A few character names are referenced, and a few lines of dialogue are referenced but the vast majority (99.9%) is original lyrics describing similar scenes and characters.
Is this a derivative work? Does this require a licence? Would it be an infringement? It is essentially a fan homage in song form.
My understanding is that as this doesn't contain any mechanical part of the original movie it is fine. Sorry if this has already been discussed, I couldn't find anything which covered exactly what I want to ask.
Update: I though I would add some examples.
Far Gone - Pictish Trail contains the line
She wouldn't stop screaming which has been acknowledged as being from the film Fargo and also uses a remixed sample from the Fargo movie soundtrack as the hook.
Are these derivative works? Would they be infringing upon IP laws without some kind of licence? And how would they compare to the situation I have outlined?