An upside-down tower, functional magic, dimension travels, stable time loops and a gunslinger.
A fantasy novel about the journey of a group of young adventurers inside a multi-dimensional upside-down tower and how the choices they make affect the future of their world and others; the tale of a mythical gunslinger in a fantasy world trying to prevent a war that could destroy the whole universe; the story of a geeky Japanese student who finds himself in the midst of this whole mess and decides to dive in instead of desperately trying to find his way back. Why pick one of those plots when you can have them all and more? Everything is connected. (extremely recommended to RPG fans)
