Glad to see this got front paged
When I noticed you didn't get in the daily top 5 I was worried this submission would fall into obscurity and not get the praise it deserves. All of the art, animation, and sound were great, and the atmosphere was perfect. The beautiful background art really helped contribute to the overall grim and mysterious feel of the movie. The story was a little puzzling at first but after a second watch I got it.
He's warned not to take the book but does it anyways.
Get's lost in one of it's spells but continues going deeper.
Meets a monster guard/prisoner, who gives him a key to access something more.
His curiosity continues to get the best of him, and he goes to use the key to access a locked room.
Discovers a mysterious book in the room, opens it, and a bad spell is casted on him.
He's now doomed to being the new prisoner of the cave, and now we know the old 'monster' was really someone other person who, just like him, didn't heed the warnings the book.
I think that's right.