本片讲述了在13年前主人公林东作为香港警察接到了保护证人的任务，由于任务的复杂性，不得以和自己受伤严重的女儿分开，而这一切其实是一场隐藏了十几年的阴谋

在2007年，一个半岛军火商看到了制造生化人的商机，于是找到相关专家詹姆斯博士，由他来研究生化人，但在这过程中发生了突发事件，名叫安德烈的生化人由于基因突变，开始大杀四方，将军火商头领击杀，并操控了他的所有部下，而研究生物人的詹姆斯博士死里逃生，无奈之下只能寻求警察的帮助，作为特工的警察林东接受命令，不得不离开自己受伤严重的女儿并担负起了保护博士的任务，经过几番大战双方损伤惨重，在博士临死前将他一生所研究的心血注入了林东女儿西西的体内，西西起死回生，但失去了记忆，13年后的一天，一本名为《机械之血》的小说引出了包括黑客李斯、神秘人组织以及隐藏身份的特工林东，三方都开始接近林东的女儿西西，想从她身上找到机械之血的秘密。

This film tells that 13 years ago, the protagonist Lin Dong received the task of protecting witnesses as a Hong Kong policeman. The seriously injured daughter left, and all this was actually a conspiracy that had been hidden for more than ten years

In 2007, an arms dealer in the peninsula saw a business opportunity to manufacture biochemical humans, so he found Dr. James, a relevant expert, and he came to graduate However, in the process, a sudden incident occurred. Due to a genetic mutation, the biochemical human named Andre began to kill the Quartet. He killed the leader of the general fire dealer and manipulated all his subordinates. In desperation, Dr. James had to seek the help of the police. As a special agent, policeman Lin Dong accepted the order and had to leave his seriously injured daughter and took on the task of protecting Dr. James. After several battles, both sides suffered heavy injuries. , before the doctor died, he injected the painstaking efforts he had researched all his life into the body of Lin Dong's daughter Xixi, who came back to life, but lost her memory. One day 13 years later, a book titled 《Mechanical Blood》The novel introduces the hacker Li Si, the mysterious organization and the hidden agent Lin Dong. The three parties all start to approach Lin Dong’s daughter Xixi, hoping to find the secret of mechanical blood from her. .