Plot
Kim Woo-hyun is the only son of a prominent police officer. Determined to make his own mark, he breezes through the police academy, and along the way racks up accolades, top of the class honors, a lot of praise and perhaps envy from his colleagues. Assigned to the cyber investigations unit, Detective Kim finds himself entrenched in an intense cat and mouse game with faceless enemies in the cyber world. Tirelessly hunting a hacker named Hades, he traces the hacker's location to an apartment building and arrives just in time to witness an actress fall to her death from the high-rise.
What appears initially to be a suicide case reveals a trail of crime and conspiracy as Hades broadcasts a video clip showing a perpetrator pushing the actress to her death. Suspected to be the perpetrator, Hades is hunted down by Woo-hyun, who finds out that Hades is in fact his past roommate in the police academy, Park Ki-young. Ki-young escapes, and later infiltrates the police headquarters in search of an important evidence proving his innocence. He is caught by Yoo Kang-mi, with whom he watches a video titled 'Phantom' that reveals a murder linking right back to Woo-hyun. Ki-young once again escapes, but calls Woo-hyun to meet up with him in an abandoned factory. The factory explodes, and one died while the other suffered severe burns. In a mistaken identity, Ki-young is sent to the hospital for treatment. Ki-young recovers and assumes Woo-hyun's identity, working together with Kang-mi to defeat the enigmatic nemesis and do justice for his friend's sacrifice.
