A train robbery takes place, resulting in unexpected catastrophe. Reid and his previously dispersed team reunite to solve the case, unaware that a greater plot is unfolding simultaneously.

A routine debt collection performed by Capshaw at a shop is complicated when the proprietress is killed and a dungeon discovered. Reid and Drake investigate, hoping to uncover Capshaw's dealings and find the girl the dungeon was kept for.

As Mathilda roams the streets, Drake finds Reid and informs him that she is alive. The team reassemble and try to locate her, while Best's investigation narrows in on Capshaw.

While Reid lies unconscious, Drake and the others investigate a series of brutal attacks on local businesses and their owners.

A brutal murder involving a wealthy titled lady occurs one evening, and the team has until dawn to solve it before the lady's husband can use his influence to have her freed.

The brutal murder of a chemist uncovers an illegal abortion racket, while Long Susan finds herself up against the chauvinism of the business world.

The murder of an American journalist, recently arrived in London to help Fred Best, may have life changing consequences for Reid and everyone else.