The Crown Prince Su Jin of Dayin is actually a woman. Since the Noble Prince poisoned the emperor, the emperor, in order to stabilize the kingdom, ordered her to disguise herself as a man. She had a rift with the Regent Prince Xiao Heng, but was tricked by the Noble Prince into having a relationship. When Su Huan tried to cast a poisonous insect used in black magic on her, Xiao Heng discovered her female identity and chose to protect her. Later, with the border in crisis and the Noble Prince colluding with the enemy, Su Jin took the initiative to go to battle.
