Ha Na and Doo Na were twin sisters who were very close to each other until Doo Na died terribly. One day, the usually bright and energetic Ha Na finds herself changing. She has superhuman strength and can do things that nobody can. Ha Na realizes that Doo Na's spirit has inhabited her body. Shin Ryu, a criminal psychoanalyst, uses Ha Na's powers to kill people who cannot be punished by the law.