Asking his father who is imprisoned in jail for money, threatening a friend who became a murderer by mistake, stealing money from his friends, Ku Dong Hyuk is the worst scumbag you can ever imagine. Living a low-life existence like a street dog, one day, Dong Hyuk gets kidnapped by a mysterious gang. Held captive for no reason, Dong Huk is repeatedly trained by the gang in a secret and inhumane way. Dong Hyuk tries to escape but fails, which makes the training more harsh and cruel than before. After finishing all the training, the gang orders Dong Hyuk to become a police detective as their secret connection.