Following the end of the grand coalition war, China's attention turns to economic rebuilding, with the state of Qin also focused on recovery. Within Qin, the ongoing power struggle between Ying Zheng and Buwei Lü's factions continues. Even though Zheng's popularity grew from his role as the symbolic king during the coalition war, Lü remains a major threat, planning to disrupt Zheng's coming-of-age ceremony, scheduled for 18 months from now.
Meanwhile, a 20,000-soldier army from Zhao approaches Qin. With no capable generals available to counter this threat, Lü suggests that Zheng should lead the troops himself. However, Cheng Jiao, Zheng's half-brother, volunteers instead, having earned Zheng's trust through their collaboration during the coalition war. Zheng accepts Jiao's offer.
Surprisingly, the Zhao army retreats shortly after engaging with Jiao's forces. Amidst these events, the internal strife in Qin deepens. Zheng can only rely on two allies: General Bi, who commands 30,000 soldiers, and Xin, the leader of the Fei Xin unit.