The Lyell are called to a museum outside King’s Cross Station, where they discover the bodies of eight victims entombed below. With the knowledge that a prolific serial killer was operating in London nearly twenty years ago, Nikki and the team know this will be a case like no other.

Nikki continues to try and identify the last of the remaining bodies in an effort to uncover any connections and find motive, while Jack and the police begin to look into several two-decade old missing persons cases which might reveal the identity of the man dubbed “The King’s Cross Serial Killer”.