While the other two seasons focused on separate stories with sup-plots connecting them, London Kills season three will follow a single case. The season kicks off with a detective looking into a young man’s fatal stabbing. It’s later known that his murderer had access to private police intelligence- does it mean they are searching for one of their own?
Cole asks her ex-partner, a detective, for help through the investigation. The detective agrees although he is killed before he can pass any details. When the squad finally gets the murderer, Vivienne is forced to encounter the demons she let go of long ago, causing her to cross a line with detective Bradford.