In the atrium of Peninsula Building, police officer Xu Tai was found seriously injured and dying. At the same time, the police also found the unconscious Inspector Ling Guang (played by Aaron Kwok) at the scene. Combined with the recent electric drill murder case, the police suspected that this case was committed by the same murderer. After Ling Guang woke up, he lost his memory, which made him unable to explain the meeting with Xu Tai, so Chen Anzhe (played by Chin Ka Lok) and other police officers accused him of being the murderer. Chief Superintendent Yu (played by Dong Yong) asked him not to intervene in the case. Ling Guang felt aggrieved, and only his good friend Ah Gui (played by Cheung Siu Fai) was left to support him. The notebook showed that Ling Guang was on leave at the time of the incident. He asked his wife Xi Ai (played by Zhang Junning) and adopted son Zai Zai (played by Tan Zhenyi) to evoke his memory at that time, but to no avail. Bloody scenes kept flashing in his mind, and his mind was extremely out of control. Not only was he indifferent to his wife and children, but he also ignored his newly divorced sister Ling Min (played by Josie Ho). While collecting evidence, Ling Guang suddenly discovered that several of the dead had a special relationship with him, and there was a bigger conspiracy hidden behind it...