Nirvana in Fire Episode 44

After Prince Jing leaves, Meng Zhi and Mei Changsu plan their defenses. On the first day of the attack, the fortress' army fends off Prince Yu's Qing Li army with a surprise attack, causing them to retreat. Later, Prince Yu orders for his army to surround the mountain in secret; this is discovered by Mei, who orders Meng's soldiers to retaliate with boulders and arrows. Consort Jing has the imperial family transferred to the inside of the fortress, and orders Yujin to recruit all able-bodied people to fight. That night, Qing Li army falls into a trap set by Mei and are forced to retreat with fewer soldiers. Meng Zhi and his soldiers fight to defend the fortress; Princess Nihuang comes with reinforcements as well as Prince Jing's soldiers, and stops the rebellion. Prince Jing captures Prince Yu for the Emperor, who finds out that his son knows his true birth mother. (Source: Wikipedia)