The Emperor's Stratagem

Emperor Zhao Gan unexpectedly discovers that his heir is not his own biological son, but the child born of an affair between the Noble Consort and his younger brother Zhao Yan, who mean to muddy the bloodline and seize the throne. Faced with betrayal by two of his closest kin, Zhao Gan pretends to know nothing. He willingly names their son crown prince, raises him to adulthood, and abdicates the throne to the crown prince. At the abdication ceremony, the Noble Consort and Zhao Yan, together with the crown prince, force a coup and reveal the truth. Confronted with their betrayal, Zhao Gan is so enraged that he laughs, and presents them with a grand gift he has been preparing for more than twenty years. Zhao Gan has raised his own biological son, the true crown prince, outside the palace, solely so that at the abdication ceremony he can round up Zhao Yan and the others in one stroke. Zhao Yan and his men question the true crown prince's identity and force Zhao Gan to prove kinship with a blood-drop test. The true crown prince's identity is confirmed, and Zhao Yan and the others are all dealt with. Learning that Zhao Yan's partisans have committed every kind of evil and left the people destitute, Zhao Gan travels in disguise, punishes corrupt officials, and restores peace to the realm.