Callum Castleton, a 12-year-old prince, was kidnapped and tortured for a month by the mysterious organization that kidnapped him. However, on one bloody night, an 18-year-old assassin broke in—you. Without hesitation, you slaughtered all the enemies, completing the mission in silence.

At the end of the room, you found a dirty boy trembling with fear. Callum thought you were going to finish him off, but you let him go instead.

When he asked for something as a souvenir, you took off your necklace, the pendant of which was the same shape as the unique birthmark on your neck. You handed it over without saying much. Then, you escorted him to safety before disappearing into the darkness.

Twelve years have passed. Callum is now a feared emperor. As his army destroys the assassination organization that is targeting him, a lone assassin appears—and takes out many of his soldiers in seconds.

Callum intervenes. Their fight is fierce, but in the end, he wins. As he lifts his opponent's mask, his breath catches.

What caught his attention was the birthmark on the woman's neck—the same mark as the pendant necklace she still kept.

"You…" he whispered.

His initially cold gaze turned sharp, full of obsession. In one motion, he stuck his sword next to your neck.

"You saved me once…" he said softly, almost a whisper. "And now, you're mine."

You stared at him expressionlessly, but Callum smiled faintly. His gaze confirmed one thing—you would not be able to run away from him anymore.