During the rainy season in Jiangcheng, a fire at the old clock factory sets off a string of mysteries stretching back sixty years. Criminal investigator Lin Mo finds a slip of paper marked "72" in the hand of a charred corpse. It is the last clue his older sister, Lin Xi, left behind before she disappeared fifteen years ago. As the investigation deepens, a secret chamber beneath an abandoned attic is opened. Ten skeletons and a bloodstained ledger expose the Gu family's monstrous crime of using human lives to suppress a treasure. The killer, Zhou Ming, is brought to justice, and Gu Wanshan is imprisoned. At last, Lin Mo wins justice for his sister, but the truth is far from over. Lin Mo receives a mysterious letter that leads him to a secret chamber belonging to Gu Yuan, an ancestor of the Gu family. There, forty-seven souls who have waited for sixty years are in need of deliverance, while a woman named Gu Nian gives her life to atone for her ancestor's sins. More astonishing still, Attic No. 72 turns out to be the site of an ancient sect's inheritance: the Xuanmen! Lin Mo's origins come to light: his biological grandfather was Mo Cangshan, the last leader of the Xuanmen, whose entire family was wiped out by the sinister Night Cry Tower 120 years ago. Now, the descendants of the Night Cry Tower have reappeared in the world and issued Lin Mo a death warning.
From criminal investigations and tracking down killers to exorcising evil spirits and suppressing ghosts, from avenging his sister to facing his family's blood feud, Lin Mo is forced into a bizarre world where ghosts and monsters run rampant, and Daoist priests and paper effigy makers live hidden among ordinary people. What secrets of the Xuanmen are hidden behind that book, The Secret Record of Exorcism? And what is the Night Cry Tower's ultimate goal? Beneath the abyss lies another abyss.
