A top modern death penalty defense lawyer suffers a car accident and, at the verge of death, time-travels to the "mirrored ancient dynasty" Dajing, becoming a death row prisoner for treason about to be beheaded. Relying on his modern legal logic and historical pattern deduction ability, he escapes death, overturns cases and slaps faces all the way, stirring up the imperial court, only to discover that the entire dynasty is a "historical testing ground" left by predecessors who time-traveled, and his own time travel was never an accident.