Born in the blood-soaked Spring and Autumn period of Chinese history, Xishi's beauty is a blessing. When she captures the attention of the famous young military advisor, Fanli, he presents her with a rare opportunity. It's then that Xishi realises her beauty is a weapon. One that could topple the rival neighbouring kingdom of Wu and improve the lives of her people. One that could avenge her sister's murder. All she has to do is infiltrate the enemy palace as a spy, seduce the immoral King, and weaken the enemy from within.

Trained by Fanli in everything from classical instruments to reading body language, Xishi quickly hones her beauty into the perfect blade. Fanli teaches her how to lie and conceal emotion, but she knows he can see through every deception she masters. A doomed attraction burns between them.

Xishi reaches the enemy palace and works to dismantle the court. But the longer she stays, the harder her task becomes. The enemy King Fuchai's advisors watch her hungrily, while Fuchai himself is kind to her. Xishi knows she is a pawn who must play by both sides' rules to survive. The higher she climbs in the tangled web of the Wu court, the farther she and Fanli have to fall.

And if she is unmasked as a traitor, she will bring down both kingdoms.