After the fall of the Holy Spirit Kingdom, true princess Natalie lives disguised as Prince "Nat." Her sister Valessa is sent to Oren Academy as a blood tribute to serve Knox, the beast-crazed leader. Natalie enrolls alongside her, and Knox shows gentleness only toward her. She bears the rare Chakra constitution—without bonding with a compatible beast, a full heat will kill her. Elder Augustus reveals the prophecy is not a blessing but a curse. On the blood moon, Natalie chooses Knox in her true identity, yet the bond mark fades. They grow close in the forbidden zone, while Valessa endures auction humiliation and sacrifices herself to protect her sister. Exposed by Fara, Natalie faces deathly heat, clutching Knox's stone: "I choose the one who is always gentle to me." As the blood moon returns, she unbraids her chest and walks to him—their heartbeats finally in one rhythm, while Archil holds the evidence of her secret.
