Update: goldpanner has translated the description of the novel provided on the page. You can read this translation below.
Sora, Riku, I would like the two of you to take the Mark of Master Exam.
"Now, Sora and Riku's Mark of Mastery exam shall hereby commence."
Master Xehanort has revived!
Their two journeys to bring peace to the world just barely over, Sora and Riku have received news from Yen Sid regarding a new threat drawing near.
In order to face this new world crisis, Sora and Riku must face the Mark of Mastery Exam.
For this the must go to the 'Realm of Sleep', release the seven Keyholes of Sleep, and gain a new power.