In ancient times, the Human Emperor, Zhao Ming, petitioned on behalf of the people and sacrificed himself to resist the divine realm. After Zhao Ming's fall, his beloved, Hun Dunzhu, risked her life to save a wisp of his soul, setting up the cycle of reincarnation for eternity. In the distant future, Zhao Ming reincarnated as Xie Xuechen, the leader of the Immortal Alliance, while Hun Dunzhu became the Holy Maiden Mu Xuanling in the Dark Domain. The two finally reunited in the mortal realm but had forgotten their past, becoming adversaries in a "righteous versus evil" struggle. Mu Xuanling saved the heavily injured Xie Xuechen in the Dark Domain and coerced him to travel together in gratitude for saving his life.

前世是重症患者的李长寿意外重生到洪荒世界，化身为一名珍视生命、不沾因果的小小炼气士，为躲避天道预言中的天下大劫，奉行“稳健”之道，一心想上天庭苟活，为此，他稳健操作，不动稳如老狗、一动“石破天惊”，他坚信打打杀杀的时代已经过去，能坑人绝不杀人，能单身绝不恋爱，奈何敌人和美人如潮水般涌来，他一不小心成了运筹帷幄的幕后大佬，卷入多方博弈之中，运作“龙族上天”，甚至那天下大劫也加速到来……
该剧改编自言归正传的同名小说。