Similarities between CoM's plot and a band's album

I came across a progressive metal project the other day called "Ayreon". I say project because it is only one person (Arjen something or other) that plays several instruments and invites singers from other bands to record albums with him that are apparently classified as "Rock operas" because the singers take on a character and the music conveys a story. The album that most intrigued me was "Into the Electric Castle", which is about various characters from different times in history being brought together to a mysterious castle that exists in another dimension or w/e, and are led through it by a mysterious voice that has its own agenda and uses the characters. In the end, the characters only vaguely remember the events that took place within the castle.
I haven't played Chain of Memories in nearly 2 years, but reading the 'plot summary' of this cd instantly reminded me of the game, at first I thought that Ayreon had possibly taken the idea from KH, but I learned that the album came out in 1998. So if you enjoy the whole idea of people being brought to inter-dimensional castles, give the band I try. I enjoy the story that the album has.