What happens when you wake up alone in an unknown place where everyone around you seems like shadows - they're there, but not really there?
(Think the spirits in spirited away movie) You don't know what you're doing here, you don't have any memories either - heck, you don't even know your own name. Trying to escape, you run into a girl who is the self-proclaimed "keeper" of the town - what does that even mean, anyway? She claims that you need to undergo a series of tests to regain your memory and leave that place, but doesn't tell you anything more. Left with no choice, you have to go through a series of riddles and puzzles to regain your memory. Whether you leave that place or not depends on how well you do. Be careful! You don't want to irritate the keeper too much - like running away from her. Who knows what she might do to you, no?

[From Lemma Soft Forums]