Naia and her mysterious companion Mano crash-land their airship in the Tower of Dreams while searching for the vanished Sun. With only ten days to escape before the tower's intense mana transforms them into monsters, Naia explores the shifting corridors and encounters an undead girl named Mary. As they uncover secrets about the tower's owner, Lord Heis, they discover that Mano possesses the unique ability to read ancient texts that could lead them to their goal.