The story begins one night in H-county’s Dabazi Village, where a floating corpse was discovered. After the villagers reported it to the police, Old Zhong and Zhang Kai came out to handle the case. The corpse was handcuffed and brutally murdered. Nie Yun ordered Old Zhong and Zhang Kai to solve the case within seven days. However, during the process, two other policemen died on the job. And when the critical witness who linked everything together was finally found, he has already been dead for seven days.