After living living her life until she was old and grey. Poison expert Lihua Lei died peacefully at an old age, surrounded by those she love. Expecting to rest in peace in the afterlife, Lihua Lei finds herself not in heaven, but instead her soul transmigrated into the body of a young 18 year old who died full of hatred and regret. The young girl's name is also Lihua Lei. She is the neglected legitimate daughter of the Prime Minister. Having been betrayed by her half sisters, Lihua finds herself poisoned, kidnapped and left for dead inside a cave for the animals to feast on her dead corpse. Lihua swore a death oath for revenge and found another soul replace her's as her soul starts to fade. "In exchange for giving me your body and letting me live a second life. This grandma promises to fulfill your last wish and take revenge on those who wronged you. To the littlest disagreement to the biggest betrayal, this grandma promises to pay them back tenfold so your soul can rest in peace." Grandma Lihua promised the young Lihua. "This grandma has already lived a life full of hardship and knows the sweet taste of peace, so this grandma isn't afraid to let them know what Lihua Lei's true colors are! This old grandma will show them not to mess with Lihua Lei!"

She was known as The Ghost, the most fearsome poison assassin in Bido Kingdom. No one lives after she attacks. No one can buy her loyalty. No one can control her. No one knows her whereabouts. She comes and goes as she pleases, blowing in with the eastern wind and leaving with the northern storm. But before she was The Ghost, she was just Du Hongmo. An orphan picked up by a family of farmers that raised her until an unfortunate event killed her foster family. Pitiful, alone, and betrayed by humanity, she survived on the knowledge that the only person she could rely on is herself. Du Hongmo meets a Goryo. A vengeful ghost who ties her soul with Hongmo and teaches Hongmo everything she knows. "The world never wanted you. You have a cursed fate. The world brought you into this world unwanted and now the world wants to throw you away without even a chance to fight for yourself." The Goryo whispered into her ear. "Meeting me is your fate bringing us together. Du Hongmo, do you know what your name means? It means Poison Iris. And before I became a Goryo, I was a poison expert. I'll impart on to you my knowledge so you'll have a fighting chance in this cursed world. And in return, you'll feed me the souls of those you killed." Forced into an unwanted life and death contract with the Goryo, Hongmo strives to live a conscientious life while walking on a thin line of good and evil. On her journey to find herself and her place in the world, she will encounter the men who will stand beside her as she takes revenge on the man who lied, chased, and broke her.