The culprit of a mysterious murder case, a boy with the heart of a dead lover. In the near future, Vega City, a city-state with advanced biotechnology. A horrific murder occurs in which a researcher is shot in the face and dies. The victim\s son, Doil, who was identified as the culprit, left an unknown statement that he saw a monster, and even the autopsy\s doctor disappeared, and the case gradually falls into a labyrinth. several years after that. Detective assistant and bodyguard Edan, who is chasing the truth of the case, encounters Doil through an anonymous tip, and learns that his dead lover Eve\s heart has been transplanted to him like a joke of fate. While Ethan and Doyle are concerned about each other, they have a gut feeling that something unusual is hidden behind the murder case. When the opportunity comes again, they come together to uncover the truth of the incident and face the shocking truth of Vega City... What is the identity of the monster that killed Doil\s mother? Was it a coincidence that he had Eve\s heart?