Anna is a young girl with a mysterious destiny, born with the bloodline of an ancient serpent king—half human, half snake. One day, Anna meets Kao, a lonely young man and her new neighbor, who is often bullied by his peers. As they grow closer, feelings begin to blossom between them. Even after discovering Anna’s monstrous nature, Kao remains unafraid. However, neither of them realizes that their connection is crossing a forbidden line.