Changmin is a genius. Despite only being a high school student , he is smart and by no means have an IQ like a kid, well his personality would gave it away though. His father, an Agent who works at the criminal unit division brought some work back home. An infamous case, dubbed as the 'Code Man' , simply because of their usage of computerised codes to commit crime. Changmin who accidently stumbled upon one of the evidence decide to decode one of them out of boredom. Low and behold he did it! His father was shocked and decided to keep it a secret, but he was still not convinced and decided to hire bodyguards for his son.

Jaejoong and Yunho was assigned by their agency to protect Changmin. While jaejoong had been so nice to changmin, yunho on the other hand was a bit cold and detached. The past Yunho wasn't like that at all. So what happened?

Can they keep Changmin safe when the secret is out? Filled with secrets and betrayal and heartbreak, will both yunho, jaejoong and changmin come out of it unscathed?