Nan Yu was originally the heroine of a classic Mary Sue romance game. When she wakes up, she finds herself transported to the era of Republican China, sharing her body with Gao Han, the male lead of a detective game. One only obsesses over romance, while the other dedicates himself to solving murder cases. The reluctant rivals are forced to work together to crack bizarre mysteries. They constantly clash yet have no choice but to cooperate, as this bickering pair takes on dangerous criminal cases in old China.
