Ghost 4 EP 4/20

Kim Woo Hyun is the only son of a high-ranking police officer. He breezes through the police academy and graduates from it with honors. After being assigned to the cyber investigation department, Detective Kim finds himself entrenched in a cat and mouse game with a faceless enemy in the cyber world. Tirelessly hunting down the hacker, alias of Hades, he finds out that Hades is his past roommate in the police academy, Ki Young. Ki young is caught. But he escapes and tries to find an evidence proving his innocence. Meanwhile, Woo Hyun tries to reveal the secrets of those that hide within the cyber world.