′′The action-packed channel, OCN returns with its new original title Equipped with unprecedented visual effects fueled by dynamic developments, has enough to blow you away as group of elite investigators team up to tackle intricate missing cases.
An anonymous letter is delivered to the police along with real photos and message directing to the crime scene. The sender is identified as Lee Jung-Soo, a convicted murderer who is sentenced to death. The recipient is Gil Soo-Hyun, an ex-FBI agent and the sender expresses his refusal to confess additional crimes he committed if the message is delivered someone else other than Soo-Hyun. When the two confronts, Jung-Soo suggests a game and several hints is provided to Soo-Hyun. Soo-Hyun team up with Oh Dae-Young, a veteran missing-case detective and Jin Seo-Joon, an ex-hacker turned cyber-security specialist in order to bring the missing case to an end.′′