Feared for her mastery of Mo clan mechanisms, Mariana is raised in the deep palace to secure royal loyalty. Her marriage to Crown Prince Sebastian seems certain, once he unlocks the mechanical wild goose lock she presents at court. In her past life, she secretly teaches him the solution, only to see the Mo clan buried alive after he ascends the throne. Reborn on the day of the imperial decree, Mariana keeps her silence and discovers Sebastian has chosen another woman. This time, she changes her fate—marrying his greatest rival and rising to rule the empire as empress.