In the tenth year of Yongle, the eighth prince Gu Sheng died in battle. Emperor Kang Le became ill due to depression and could not afford to fall ill.
In the eleventh year of Yongle, the general Liu Sheng led a heavy army to surround the imperial city and made the sixteenth prince a puppet emperor. The former prince Gu Yan was banished to the cold palace.
In the twelfth year of Yongle, the assassin Po Feng abducted Gu Yan, who was thrown into the cold palace.
Since then, a bloody drama of seizing the throne has officially begun.