CID officer Tong gets himself entangled with a gang of killers from mainland China, who are out killing criminals to rob them of their money, and using an ideological basis to justify the killings as protecting mainland China from the criminal scum of Hong Kong.

Rumor has it that “Black Moly”, the Indian head of a gang has returned. His former subordinate Velu is released from prison, he refuses to follow the same path as before. But he is misconstrued by his buddy, Sonu that Velu betrays him. Sonu accepts the task for killing PTU’s Team Head. Sam and May from PTU and Velu can’t easily leave themselves out of account.

Two tactical unit leaders are forced to put aside their differences to help catch a group of robbers.

In PTU, a young police officer is thrust into the gritty and dangerous underworld of crime and corruption as he tries to solve the murder of a fellow officer. This intense thriller takes place over the course of one night, as the officer navigates through shootouts, police brutality, and a youth gang. The investigation leads him to an arcade game where he must confront his own demons and make difficult choices. With scenes of blood, violence, and gore, PTU is a gripping crime drama that exposes the darker side of law enforcement.

Tensions flare between PTU officers and the Complaints Against Police Officers unit when a security camera captures a triad member being brutalized by PTU officers.

After a late-night triad dispute leads to the death of an innocent civilian, PTU officers take action by investigating triad activities in the area.