sentences:  As "Birth by Sleep" is a prequel of the first "Kingdom Hearts" title, the staff decided to add Zack to the title as he is the protagonist of the "Final Fantasy VII" prequel, "".Master Xehanort brings a comatose Ventus to the Destiny Islands after the latter's heart is damaged; a newborn heart senses Ventus's heart and connects with it, saving him.Years later, at the Land of Departure, Terra and Aqua take an exam to achieve the Mark of Mastery.