Code 404

Top cop John Major is killed after a failed operation. But then the Met brings him back - as an AI prototype.

After he and Carver are given a new assignment by Dennett, a suspicious Major prefers to stake out Kellys work as he has a hunch shes been seeing someone else.

To Carvers bewilderment, Major reveals that he is going to move back in with Kelly. Parfit discovers disturbing information in the AI Ethics files.

Major, Carver and Kelly have gone their separate ways. Things are looking up for the AI-enhanced Major, whilst Carver is gunning for a promotion and is knee deep in a new case.

DCS Dennett officially reopens the Chelsea Bridge case, reuniting Major with his absent father, Clifford, who failed to solve the case 20 years earlier. As Majors AI becomes increasingly unstable, Dr. Parfit and Carver clash over the solution.

Carver deals with an unstable Major, and Dennett calls in a favour from Millikan Biotech. When the detective inspectors are assigned to a witness protection case with some familiar faces, Carver learns shocking truths and confronts Major.

Major and Carver reunite, but tensions remain high. When a police officer is murdered, Carver becomes hell-bent on solving the case, Major has an epiphany and resolves to become a better man, and both detective inspectors are out to prove themselves.

Major faces an outside threat to his AI, and Carver contends with a serial killers twisted games.

Chalmers, the former police commissioner who has plagued Major since the day he was reanimated, faces trial. With Major busy testifying, Carver is running out of time to decipher the latest clue and save the killers next target.