Sang Mi, the legitimate daughter of the Sang family, is actually a transformed flower demon. Due to an accident, she left a secret in the garden, which was noticed by her fiancé delivering wedding robes, Xie ZeyI, the Minister of the Court of Judicial Review. After marriage, the two joined hands to investigate cases; she tried her best to hide her demon form, while he relied on evidence to protect her thoroughly, gradually developing romantic feelings after a marriage before love. Prince Liang used a series of serial suspicious cases to investigate her origins, and when they encountered danger in the southwest, Sang Mi revealed her true form to save her husband, and Xie ZeyI chose to accept her after being shocked. The two faced the sealed old case and family secrets together, building trust in testing and protection.