Xuanyang Cave at Shanhai Pass is a "rift in time and space," where the obsessions of generations of gatekeepers, refugees, and soldiers have gathered to form "Pass Spirits." After Lu Yuan accidentally falls into the cave, he gains the ability to speak with the historical dead and is forced to take in three "ghost disciples" from different eras. He helps them fulfill their unfinished wishes, ultimately uncovering the thousand-year-old secret of Xuanyang Cave.
