Prosecutor Jun Wu Jiu is sentenced to prison after he was framed for a crime he did not commit. Filled with hatred, he is determined to avenge his teacher and fiancee. In spite of his circumstances, he relies on his wisdom to solve many cases and uncovers an earth-shattering secret. Can the mayfly shake the tree? Can a prisoner exact justice?

被诬陷的小小推官君无咎，身陷刑部大牢。 他虽然有满心的仇恨，想要替师傅和未婚妻报仇，可是蜉蝣如何能撼动大树？ 看阶下囚如何断命案，从而掀开了震惊朝野的惊天秘密。