Hyunsoo, a private investigator, visits a lodge requested by a client asking to get back her dog. While waiting outside, a prosecutor falsely accuses him of kidnapping the client. While arrested, a serious car accident occurs and people mistake Hyunsoo as the prosecutor. To find the real criminal, Hyunsoo pretends to be a prosecutor. Hwajin, an elite prosecutor who had been demoted while trying to catch Dohoon, a dirty lawyer, meets Hyunsoo. Finding out Hyunsoo`s case is related to Dohoon, Hwajin collaborates with Hyunsoo. Consequently, they realise that there is a hidden truth behind the crime.