After the September 18 Incident upends their lives, Lv Xin marries Cai Qihai while secretly vowing revenge against her former childhood sweetheart, Tang Han, who has betrayed his country and murdered her father. As Tang Han returns to Wulin on a secret mission tied to enemy forces, Lv Xin is drawn into a dangerous web of espionage, assassins, and hidden identities, where the line between loyalty and betrayal grows ever more uncertain.