An Irish dynamiter is sprung from prison and barely a day later a prominent opponent of The Home Rule movement is murdered. Chief Inspector Abberline is convinced that the Irish Republican Brotherhood is once more about its work and orders Reid to send the Irish DC Flight undercover into Whitechapel's Irish community.

Investigations into the brutal slaying of a Telegraph Boy lift the lid on a vice racket run from the offices of the GPO. The case leads Reid to the heart of the one of the city's most august financial institutions. Captain Jackson seeks ever more perilous means of ridding himself and Long Susan of the suffocating debt they owe Silas Duggan.

Churches and synagogues are being burnt and desecrated in Whitechapel and Reid suspects the same hand behind the various attacks. Meanwhile, the all-too-brief domestic happiness that Sergeant Drake has enjoyed is disrupted by the arrival of a friend from his wife Bella's past, the mysterious and charismatic scholar, Gabriel Cain.

The reckless and unreliable oldest brother of Captain Jackson arrives at Whitechapel with a valuable uncut diamond. Reid and Flight are attracted to the situation of a local craftsman who has been defrauded by a large firm.

[Season Finale] As Reid and Drake find themselves powerless to resist the awful temptation of a final reckoning with K Division's Jedediah Shine, so Jackson and Judge's ever more desperate attempts to profit from that stolen diamond lead them into the teeth of the murderous agents of the De Graal monopoly.

Four years have passed. Time that has seen Reid, Drake and Jackson split and isolated from one another. But when the robbery of a goods train leads to a cataclysmic locomotive disaster on Leman Street itself, the men and their resentments, are reunited to seek its cause.

A routine murder inquiry in a curiosity shop reveals a secret underground cell. The murder itself may have links to Long Susan's burgeoning property empire, Obsidian Estates, but Reid is far more concerned as to the identity and whereabouts of that cell's prisoner, a young girl kept there for many years.

Chief Inspector Abberline asks Drake to take over the helm of H Division. But Drake is far from keen to preside over his friend's desk. The inexplicable death of a clairvoyant takes our team into a world of devious charlatans capitalising on the grief of a sorrowful community.

As a lost girl wanders the dangerous streets of the East End alone, Detective Inspector Drake must try to find his old friend Edmund Reid and bring those responsible to justice. When tangible proof to finally bring Capshaw to justice arrives, attempts to arrest him will deliver devastating consequences.

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.

The dark and corrupt streets of Whitechapel are witnessing a new breed of tourist; one from the higher realms of society wanting salacious entertainment. Yet Lady Montacute's curiosity means she now stands before the men of Leman Street charged with the vicious stabbing of a local woman.

Edmund Reid, Homer Jackson and Long Susan Hart come together to bring Bennet Drake's murderer to justice