I agree with strolen. The possibilities are endless. You can make it sort of like Myst, and have it focus on puzzles to get the book, or a quest bent on finding who is responsible for all the demons roaming the island. Go to Comment
It has been said that within the mountains (or was it the darklands?) there dwells a fluffy creature of immense cuteness. This creature is so adorable that all who encounter it are filled with joy so great their mortal forms cannot contain it. And they explode. Several magic institutions are desperate to study the creature or better yet capture one to prove the theory of an elemental plane of "D'Awwww".