Situ Minghao (played by Ren Quan) and Zhao Yong (played by Qiao Renliang) are colleagues and friends who work in the same magazine. The two have known each other for many years and their friendship is very strong. Recently, they focused the magazine on a human organ reselling case. During the investigation and evidence collection, Zhao Yong disappeared unexpectedly. What awaited Situ Haoming afterwards was the news of Zhao Yong's death.

What Situ Minghao didn't expect was that Zhao Yong's death was not the end. Not long after the tragedy happened, the staff of the magazine began to receive death emails from Zhao Yong one after another. What's even more frightening is that those who received the mail really died one after another. The shadow of death hangs over the entire magazine, and everyone is secretly guessing who is the next target of the terrorist killer, and who is that killer.