She was a famous assassin who had killed important figures, but ironically, she was killed by her own lover.And when she thought she was dead, it turned out she was occupying the soul of a young girl who was tricked by her own family.'Because I have been reborn, I will take revenge on the people who planned my murder and also teach a lesson to the people who underestimated the girl whose soul I reside in!'However, things become complicated when she has to marry a cold man, whom she spent the night with.