Him Law is a Probationary Inspector in the Hong Kong Police and aspires to be the fastest promoted Inspector in history. During a drug raid, he encounters a suspect, Edmond Leung. Seeking to avenge a personal matter, he allows Edmond to overdose on drugs. Later, Him finds out that Edmond died and feels extremely guilty. He is only able to slowly recover with the help of psychologist Jolie Zhu.
Mainland cop Wayne Yang, nicknamed "Bullet", comes to visit his friend Edmond, only to discover that he had fallen to his death after overdosing on drugs. Bullet is greatly surprised by this and believes that it is impossible. He resolves to find the truth to prove his friend's innocence. Soon after, Bullet discovers that Edmond's death is related to a drug network operated by the Hong Kong triads. The drug network is colluding with foreign drug cartels to open up the vast Mainland market! Bullet immediately notifies the Hong Kong Police. The Mainland and Hong Kong police join forces to destroy the cross-border drug network.
Infernal Affairs will be airing on iQiyi and myTV Super beginning December 21. The series has three seasons, consisting of 12 episodes each.