Yin and Ning are very close as sisters; Yin cares for her sister, who is armless, as they travel between villages, putting on performances; when they arrive in the ruins of a village, they find a mysterious bamboo writing strip.

The two sisters love Zhao like a brother, but that eventually turns into romantic love; while playing in the field as children, they discover a broken construct; Zhao gets drawn to the workings of the strange machine.

The girl who appeared out of the tianshu bamboo writing strip is Yun, a doll made using Mujia; Yun calls the sword that appeared out of the tianshu the legendary Xuan Yuan Sword; through Yun, Yin and Ning acquire new power.

Yin and Ning meet Tuoba Yuan and Can Lang during their travels; they are members of the rebel forces fighting against the Taibai Empire; they claim it is the duty of one who possesses the tianshu and the Xuan Yuan Sword.

Yin and Ning run into a Taibai transport unit while traveling; they follow the unit to a farming village with bountiful fields; the Taibai official at the village grows fat while making the villagers suffer under heavy taxes.

Sisters Yin and Ning are joined by rebel forces Yuezhi and Rou; when they are invited to join the rebel army, Ning enthusiastically agrees, but worried for her younger sister, Yin is opposed to the idea; Ning resists her sister's concern for her.