After Olivia's adoptive sister, Princess Teresa, died in battle for her country, the mourning period had not yet ended when the kingdom hurried to stabilize the political situation and arranged the royal marriage that had already been decided upon.
Olivia was an adopted vampire demon, an imperial daughter who existed like a shadow.
Yet she was to marry the chancellor's daughter, Aelesty, her late sister's fiancée, in her sister's place!
Olivia had originally wanted to work with Aelesty to investigate the suspicious circumstances surrounding her sister's death in battle.
But she suddenly realized that Aelesty seemed to have become rather strange after her sister's death.
When courtiers mocked Olivia for her impure bloodline, Aelesty would fiercely rebuke them all and declare her claim over Olivia.
When Olivia secretly infiltrated the demon lands to investigate magic that could bring her sister back to life, Aelesty instead dragged her straight back to the imperial palace and gave her a stern scolding, forbidding her from taking such risks alone again.
Olivia had her suspicions about these overstepping gestures, but she never dared to consider that possibility.
How could her future sister-in-law have strange feelings for her? She must have misunderstood something.
But when she finally found a clue about how to resurrect her sister, and, holding her sister's holy sword, entered their bridal chamber to excitedly tell Aelesty they could finally be free of this, Aelesty merely smiled softly, then asked her for something for the first time.
"Let me become your blood servant. That's what I desire from you most."
Only then did Olivia belatedly understand the subtle feelings Aelesty had for her.
"How could you be my blood servant? No, no way!"
