When she was 5 years old, in order to protect her from being kidnapped by the betrayer of the Jiulan family - Jiulan Li Tu, her mother Jiulan Juri used her own life to seal Yuki's full abilities and memories as a vampire, allowing her to survive as a human. His father, Jiu Lanyou, was killed by Li Tu with a hunter's sword in a battle with Li Tu. Now that she has awakened her vampire abilities, she knows her true identity—a pure-blood vampire! She is the only pure-blood princess of the Jiulan family and Shu's biological sister - Jiulan Yuji! She was born as the wife of Shu. For Zero, she hopes to protect him and prevent him from being harmed. However, after becoming a vampire, she has a deep sense of guilt for Zero as a hunter. However, the two opposites cannot be the same as in the past. Getting together can only bring harm to each other and they can only choose to separate...