S1, E4: Du Zixin tells Renjie that CODE is an urban legend circulating in the realm of the dark web for many years. This APP fulfills all the wishes made to it provided that the users return the favor. The sinister part is that this seemingly innocuous APP has been involved in numerous fatal accidents. Even Du Zixin’s family members have been victims of CODE. Upon investigations, it is discovered that seemingly unconnected incidents are actually related due to the machinations of CODE. ‬‬‬‬‬‬‬ As a police detective, Liang Renjie is committed to uncovering the truth. As a journalist, Du Zixin wants to reveal what goes on behind the scenes. The two teams up with a world-renown hacker by the alias, Hank. The trio decide to cooperate to unveil the hidden truth behind the mysterious CODE.