This book reads a lot like someone wrote up whatever happened in their RPG game – especially for the first 40% or so where the main trio are journeying ever-deeper into a dungeon, fighting rats and enchanted skeletons and stuff.
I guess the core plot is OK, but the book is extremely slow and the characters all feel pretty generic. There’s a lot of emotional whiplash too… like there’s a scene where they have to fight umpteen mooks at once, and they’re all having a great time knocking them out but then they accidentally kill one and this is The Worst Thing Ever. Then very late in the book, they’re all crying and upset about something Very Bad that’s about to happen, but the evil person doesn’t know their names so this immediately cheers them all up and they have a good giggle, even though the Very Bad Thing is still just about to happen. So, eh. I think this could’ve been saved with some rewriting, but clearly it wasn’t.