The Yīng and Zhāng kingdoms are engaged in a 200 year war. In order to survive a terrifying enemy with a sinister motive, both kingdoms must set aside their feud and form an alliance through marriage, much to the ire of their people and the Wáng Píng clan.

After Princess Yīng Mîn Jíng's mother dreams she will unite the kingdoms to destroy a deadly foe, she is sent away to cultivate her mind and body. She is a gifted healer loved by all, known for her kindness and compassion...until her family is threatened.

Prince Zhāng Jié Qiáng has a reputation as a heartless brute and womanizer. He believes diplomacy is a waste of time and prefers a swift, violent end to dissidents. Citizens fear him, officials ridicule him, and the king believes he will never understand honor or empathy...until he is transformed by his one true love.

In a coincidence scripted by Fate, Mîn Jíng and Jié Qiáng meet at a festival in her kingdom. Donning masks, he and his companions rescue her from a perilous situation. In her own mask, she guides them through the village, not realizing they are spies of the enemy kingdom. Jié Qiáng becomes intrigued by the kind and carefree girl and vows to make her his wife.

Soon after, both find their way onto the battlefield: Jié Qiáng to fight, Mîn Jíng to heal.

When the political marriage alliance is announced, Jié Qiáng refuses to forget his Little Crane. Dreams of her kept him alive while imprisoned by the Wáng Píng, and he will never allow anyone to take her place.

Mîn Jíng loses all hope of reuniting with her Black Butterfly, fated by her duty to her people. Only dreams of him could dispel her nightmares of war, and she feels this enemy prince will never love her as only her one true love can.

Will their alliance be enough to defeat the cruel and bloodthirsty Wáng Píng? Can their love overcome dangerous attempts to destroy them? Will she succeed in saving their kingdoms, and will he succeed in protecting his beloved wife?