A murder inquiry in a curiosity shop reveals a secret dungeon and signs of a captive girl.

Alex le Shayne, a mysterious clairvoyant is found dead at the local performance place. Jackson presumes poison has a part to play. As Reid is missing Drake steps in to investigate. Elsewhere Susan continues to care for Mathilda and plans to send her to Switzerland.

A destructive gang of youths unleash hell upon the streets, but it's not until daylight breaks that the true horror of their brutal work is revealed. The trail leads the team of H Division into the heartland of one of the city's oldest trades - the London Breweries - where conflicted loyalties reign, and grief and anger create a potent concoction.

The recovering Reid finds the unconscious Lady Vera Montacute in Whitechapel next to the corpse of a flower seller.