In his past life, Leo was imprisoned, tormented, and killed by Damian, a ruthless mafia kingpin. Reborn, he intended to live under a false identity to stay far away from danger. But to save his gravely‑ill younger sister, he is forced to become the devil's substitute plaything once again. Trapped in successive harrowing misfortunes — public humiliation, a failed escape, and the supposed death of his sister — Leo makes a desperate choice. He drinks poisoned wine, casting the cruellest curse upon Damian with his own life. Three months later, Leo survives but loses all his memories. The brutal mafia overlord tames his ferocity, lying that the two are deeply‑in‑love lovers. He weaves a gilded cage disguised as affectionwith overwhelming tenderness. Yet when a blood‑stained diary flutters open, the chilling blood‑scrawled word ""RUN"" awakens the terror buried deep within Leo's soul.