I was a boy wizard going to a wizard school. The dream was certainly Harry Potter inspired, but the school and its staff more resembled schools from my life and from other fiction than from the HP universe.
I was accused of a particular crime by a faculty member that I never knew what it was. It was a crime so severe, and the accusing authority was so trusted, that my fate to be punished for it was absolute. Nobody believed in my innocence, including my (not IRL) parents, who were part of the process for conditioning me for my punishment. I got this sense that my crime was not one of doing but one of being – like perhaps I was discovered to be the reincarnation of some evil demon or whatever.
People pitied me more than anything. They did not hate me, but I could not run free, and while my parents and others empathized, they were certain of my guilt and would not allow me to roam freely.
Only one person tried to foster my escape, and that was a person reminiscent of professor McGonagall from Harry Potter. She tried to sneak me out past some invisible rabbit stuffed animal creatures that guarded the mansion I lived in, but was apparently not successful.
So I was to be put in a prison in another dimension, and once the preparation was complete, I was sent to a place that was a massive interior larger than any structure created by humans. It was a tunnel through a dimension. The walls and ceiling were not visible, just an indistinct blackness. The only features of this interior void were a vast ocean of glowing liquid below me, and this strange structure of fluorescently glowing piece of geometry vaguely suggesting a tunnel through this dimension above me. There was a massive feeling of dread, because I knew that once I reached the bottom of this dimensional shaft, I would never escape it, never die. My future was an eternity of the same thing. This idea is horrifying.