PandoraHearts, Volume 5 (Pandora Hearts #19-22)

Guided by Jack Vessalius, the man from Alice's memories, Oz wanders back into the world of lost memories in search of Alice. There, he stumbles upon the devastating tragedy of Sablier, the century-old disaster which sent the old capital into the Abyss, an incident of which no one has any recollection...except Alice, who was there?! When Oz discovers the truth of the memories Alice so desperately wants to forget, the powers of the B-Rabbit will spiral out of control and threaten the lives of all who are trapped within the dreamlike dimension, including Alice herself...