Detective Liang Renjie is devastated when his long-term girlfriend dies in an elevator fall accident. He is furious when this bizarre case is ruled an accident. Renjie firmly believes that this case is not as simple as the police make it look like. He therefore decides to challenge the system, which upsets his superiors and colleagues to complain about him. Around the same time, Fang Kai, a drug dealer he arrested before, is released early on parole, which means that his informant is in grave danger. While he is facing this predicament, he suddenly receives a strange phone call. The person on the other end instructs him to download a mysterious APP called CODE. Little does he know that this phone call is about to change his destiny.