Blade Of Heaven (Blade Of Heaven #6)

When Soma and friends fall through a whirlpool, they plummet into the murky depths of a lake, finally arriving at a mysterious castle under the water. There Soma meets up with the Eastern Race Wiseman, who informs him that he is the chosen owner of the Heart Sword. He also instructs Soma about what he must do to improve his swordsmanship--and ultimately master the Chunwangshin Sword!