"Seven Evil Detectives" tells the story of the wealthy businessman Liu's family who was wiped out overnight in Xiangzhou City of the Daqian Dynasty. On the night of the blood moon, seven young people with different talents - Su Yichen, Lin Yushang, Xiao Yifeng, Ye Jinxuan, Mo Wuhen, Zhao Lingyue and Chu Xingyuan - formed a detective team determined to uncover the truth of this horrific case. They explored the eerie Liu family's old house and found various mysterious clues, such as blood-stained cloth, bloody daggers, blurred account books, etc. As the investigation deepened, they discovered that there were many conspiracies involving powerful people in the city behind the case. In the process of pursuing the truth, they repeatedly fell into crisis and encountered life and death tests, but they never gave up and gradually approached the astonishing truth hidden deep in the darkness.