[3] The third and final series, The Secret of Springheel'd Jack, released over 2015 and 2016, features Jenny Runacre and Matthew Kelly, and deals with the 1877 Aldershot barracks incident.

Metropolitan Police Constable Jonah Smith and his chirpy sidekick, Toby Hooks, are called to Clapham churchyard to investigate an attack on a young woman, Polly Adams, who insists her assailant was the devil.

Meanwhile, at Dover, vicious cockney killers Chough and D'Urberville are performing their own parallel investigation into the whereabouts of Charlotte Fitzrandolph, who is returning to England from Europe, and has with her a family heirloom, the Burning Truth: a pendant with seemingly supernatural properties.

Smith's inquiries soon bring him to the attention of Lord Wayland, a powerful Tory landowner, who is keen for Springheel Jack to be caught before his reign of terror gets out of hand.

Meanwhile, at a lavish masquerade ball, Lord Wayland entertains the Duke of Wellington and other guests – including the Marquis of Waterford – before excusing himself to hold a secret meeting... with Chough and D'Urberville.

Smith visits the Morgan Arms, and learns from the landlord, Burden, and barfly Tom Millbank, that the Duke of Wellington is to lead a hunt for Springheel Jack.

Then he and Hooks hot-foot it to the scene of the crash and learn from the concussed coachman that his lady passenger was heading to Scratch Row – the location of the fire in which Smith's parents died.

The high priest is none other than Lord Wayland himself, and his ritual incantation causes the Burning Truth to emit an otherworldly noise, alerting the devil-worshipers to their presence.

Knocked unconscious and stuffed in a carriage, Smith is delivered to Lord Wayland at his riverside mansion, with Charlotte and the Burning Truth following at a discreet distance.

All Wayland now needs to meet his master face-to-face is the Burning Truth, and he suspends Smith above a vat of boiling oil in order to force its whereabouts out of him.

But Smith's obsession to capture Springheel Jack has only just begun... Famed penny dreadful writer James Malcolm Rymer tells his 'one true story' which took place in 1845 when he was a struggling newspaper hack.

His tale commences on Jacob's Island, Bermondsey, where a 13-year-old pickpocket, Maria Davis, is pursued by a spring-booted, fire-breathing maniac, and killed with a burst of flame.

There seems to be a connection between authentic Springheel Jack sightings and the tour dates of a travelling theatre company known as the Harlequin Players.

Smith agrees to meet Charlotte that night at a nearby penny gaff at the Fighting Cocks Inn where the Harlequin Players are due to perform.

The following magic act consists of doddery magician Cuthbert Leach, aka 'The Great Majesto' and his 'lovely assistant', the pugnacious Lizzie Coombe.

While a performance of The Murder in the Red Barn distracts the other patrons, Charlotte warns Smith that she has made a terrible mistake by confiding in a mysterious man she met in Paris.

Hopcraft admits that he's the man that Charlotte met in Paris and goes on to reveal that he, like Smith, also lost his parents in the Scratch Row fire and saw Springheel Jack rise from the flames.

Hopcraft also stows aboard, and just before the train departs Garrick gets on as well, ordering Sergeant Skeres to arrange for a detachment of soldiers to arrest Smith when they arrive at Slough.

As the story comes to a close, the narrator – the old Rymer – reveals that Smith and Lizzie got married, and admits that while the truth about Spring-heeled Jack may be important to some, he is content with the legend.

Springheel Jack attacks Aldershot barracks and despite huge resistance by the British army, steals back the Box of Emet.

Word of the attack reaches Prime Minister Benjamin Disraeli from his Foreign Office adviser Anstruther, and he fears the Germans or Russians may be behind the raid.

Anstruther thinks not, suspecting that the old rumours of Springheel Jack may be true, having been warned about this scenario by a missing agent of his, code-named 'Cheshire Cat'.

Anstruther seeks Smith out at his lodgings and discovers him to be an ageing, alcoholic widower, no longer interested in hunting Springheel Jack, and unwilling to help.

Meanwhile, the news of the Aldershot attack reaches Prussian spymistress, the Countess de Sadesky, who shares Smith's one-time obsession to capture Springheel Jack.

Anstruther shows them an intercepted German telegraph that points to the abandoned Scratch Row underground railway station as Sadesky's next port of call.

Smith and Hopcraft have fallen through to a new tunnel of fused ceramic, created when something large and hot ploughed through the earth at high speed... on the night of the Scratch Row fire.

Sadesky reveals that rather than being mere German agents, she and Jaeger are in fact leaders of the Bavarian Illuminati, and intend to sell the secret of Jack's technology to the highest bidder, whether that be Germany, Russia or Great Britain.

Despite Smith and Hopcraft's warnings, Sadesky tampers with the controls of Jack's isolation chamber, and the ship's automatic defences come to life and disintegrate her with a death ray.

Drawn north to Liverpool, Hopcraft finds himself in Sefton Park during a fresh Springheel Jack scare, and is met by the spaceship as it returns.

In a post-credits scene set on Barnes Common in 1977, a pair of government agents in a dummy TV detector van have a close encounter with another Spring-heeled Jack.