Princess, Why Are You in My Room in the Middle of the Night?

The Su Dynasty, in an unspecified year.

The Prince of Zhenbei commands a powerful army and has won such great merit that he overshadows the emperor. He harbors ambitions of rebellion.

But his younger sister is the empress, and the emperor has no sons.

That makes her eldest legitimate daughter first in line to the throne.

So the Prince of Zhenbei chooses to bide his time rather than compete for the throne with the younger generation.

However, the emperor has an eldest legitimate daughter by his first empress who was lost among the common people. So the Prince of Zhenbei works to win over the martial world while interfering in the affairs of the great clans.

The turmoil among the great clans repeatedly puts the first empress's eldest legitimate daughter in danger.

At the same time, claiming that she is his enemy from a dream, the Prince of Zhenbei issues a kill order for anyone suspected of being Princess Yongle, the first empress's eldest legitimate daughter.

And so the story begins...