The Middle Realm - The Trinity Chronicles, #2

When Ash uncovers a familiar symbol in the Middle Realm, a hidden prophecy is revealed which he is sure constitutes a warning to the Guardians. As he unearths further secrets, Ash discovers that the concealed spells within the Book of Elements not only safeguard the Guardians from one another, but prevent them from uncovering the seed of their destruction. When the Ghouls steal the book for their elusive master, Ash embarks on a mission to recover it.
Without the book, the Guardians' return to the Third Realm to overthrow Drakon, the Dark Guardian, will be futile. But a force far more sinister than Drakon is manifesting. Time is running out and at the turn of the millennium the August Moon's appearance will signal the beginning of a new era or the end of all time. Will the One, a more powerful being than the Fifth Guardian, finally appear?