民国年间，盛传阴宅下葬风水之说，所谓“发财靠阳宅，升官靠阴宅”一说风靡。阴阳先生一职更是有堪龙穴、阴阳宅断的本领，深受追捧。有“地仙”之称的郭阴阳（高雄 饰）来到灵山镇寻找恩人郑翁（侯桐江 饰），发现灵山镇深藏着的神秘的鼠嫁、风水绝户之地的死亡之说。阳人住阴宅，回门之日冲煞头七之夜。偷风水而起家的两兄弟，守孝三年，真假孝心背后却隐藏着关于鲤鱼穴的禁忌怪谈。阴人回阳宅，每夜寻找红衣的长发女子。一切线索将三段故事牵扯之中，因果不空，循环不止，背后的谜底究竟如何？

　　Agroupoftiredcommutershavecaughtthelasttrainhome,readytohopintotheirbedsforthenight.However,theirtrainsoonveersoff-courseandcrashesintoanabandonedtunnel.Thethreesurvivingcommuters;withdrawnmotherYiLing,hersonLucas,andstudentJanice,areforcedtobandtogetherandsurvivethenight,aswellasavoidthemysteriousmonsterhuntingthem.YiLingstillsuffersfromflashbackstothecaraccidentthatkilledherhusbandandnearlytookLucas`lifetoo.WhenLucasissnatchedawaybythemonster,hermaternalinstinctsaretested,andJanice`sideasoffamilyarechallengedassheremembersherdifficultrelationshipwithherestrangedfather.Backatthesubwaycontrolheadquarters,theengineersdotheirbesttomakesenseofthesituationandrescuethesurvivorseee

一封寄给吴邪已故爷爷吴老狗的神秘来信，打乱了吴邪、张起灵、王胖子的退休计划。信件指向外蒙古的一个“彗星”墓，铁三角决定一探究竟，却意外卷入一场超乎想象的冒险。心怀叵测的蒙古悍匪、“彗星”的逃生倒计时、诡异的墓室规则，还有那个看不见的“它”，铁三角不得不放手一搏……