Patsy the mudlark is staggering through the streets of London. She approaches a policeman and explains that she feels rather strange, like her mind is turning black. She requests to see Professor Litefoot in his mortuary, but the officer refuses to let her and tells her to leave before he arrests her.
Patsy passes by the New Regency Theatre. A man outside is selling tickets to the show. Patsy asks to see Jago, but the salesman tries to barter her off with cheaper rates, but Patsy gets restless and demands once more to see Jago. The salesman tells her he’s not here, which distresses her as she’s feeling rather queer in the head. Her voice suddenly turns monotonous and she states that she no longer needs Jago as she knows what to do now…before shouting that it’s the darkness in her head!
At the Red Tavern, Ellie is hard at work tending to the bar. Patsy stumbles in completely dazed and confused. Ellie takes her to one side and talks to her. Patsy asks Ellie to help her as she complains about the darkness in her head telling her to return to Gride’s warehouse. Ellie is dismissive of Patsy’s mumblings and assumes she’s drunk and so she leaves her be.
Patsy meets with a friend of hers, Old Tom the beggar. She offers him a job for some easy money. All she needs him to do is to shift some barrels from a warehouse to a ‘friend’s’ lockup.
Inspector Quick, off duty and in civilian clothes, visits the Red Tavern. He asks Ellie if she had seen either Jago or Litefoot. Ellie mentions that neither of them have visited the Tavern in a while. She mentions Patsy had visited not long ago and how she needed to get back to the warehouse. Coincidently, this warehouse was what Quick needed to talk to Litefoot about as he and the police have yet to find a way to dispose of the barrels of amniotic fluid and were looking for a safe solution. Quick decides to visit the warehouse to check on Patsy.
Old Tom and Patsy have finished loading the barrels of amniotic fluid onto two horse-drawn wagons. He complains about Patsy withholding his pay, but Patsy shushes him and tells him to take his load of fluid to the lockup as quick as possible, even promising to double his pay should he get there before she does. With that promise, Old Tom speeds off down the streets, with Patsy giving chase.
At the Red Tavern, Ellie gets a surprise as Jago and Litefoot arrive in the establishment. Both men discuss their recent adventure involving the Darkling Façade and their amniotic fluid. They hope that Quick has managed to get things under control and that Patsy isn’t suffering from any ill effects after her exposure to the fluid. Ellie mentions that Patsy visited earlier. She notes that she was acting stranger than usual and that she mentioned going to the dockyards. She further states that Quick also visited and mentioned his intentions of visiting the docks as well. Litefoot voices his concern to Jago that if an agent under the influence of the Darkling Façade got hold of the barrels, they can infect the whole of London and possibly the World. Both seem to complain about their heads becoming rather riddled with dark thoughts…They both decide it best to find Inspector Quick…
On the streets of London, Patsy is speeding through the streets with her wagon of barrels. She nearly crashes into a horse-drawn carriage. The owner and Patsy begin to argue until a nearby policeman breaks up the commotion. The policeman notices Patsy’s wagon and recognises it as a reportedly stolen wagon. Patsy quickly speeds off down the road but doesn’t get far and crashes into a station wagon. The police try to apprehend her, but Patsy fights back while ranting madly. She bites one of the policemen which causes him to bleed, thankfully his fellow officer manages to handcuff her before she does more damage.
At the police station, Jago and Litefoot arrive and explain to the desk sergeant that they’ve heard about Patsy’s altercation with the police and the theft of the wagon full of fluid. The sergeant leaves to fetch Inspector Quick. Moments later, Quick arrives and explains that when the police apprehended Patsy, they found only a few of the barrels accounted for. What may have happened to the rest of them or why Patsy stole them they cannot say. But because she was ranting, raving and attacking his officers, Quick had her confined to a correctional mental hospital…
Jago, Litefoot and Quick visit the mental hospital where Patsy is confined. He opens Patsy’s cell and they find her restrained in a strait jacket bound in chains. Patsy is angrily ranting and raving madly. The trio ask her about the missing barrels, but Patsy refuses to answer. With no way of making her speak, the Infernal Investigators and Quick leave her in the cell.
Outside the cell, Litefoot requests Quick that he may be permitted to speak with Patsy alone as he has a deceptive plan to make her talk. Quick allows him to and reopens Patsy’s cell once more to let Litefoot in. Quick closes the cell behind him. Litefoot tells Patsy that he is aware that she is under the Darkling Façade’s influence as she was covered in their amniotic fluid when the water tanks were destroyed by Jeremiah Castle. He then reveals a disturbing fact…he and Jago are also infected! He asks once more where the barrels are kept so that he and Jago can continue their nefarious plans. Patsy reveals that she had stashed the missing barrels in a lockup underneath a railway bridge at Jacqueline’s Wharf. Litefoot is grateful for her cooperation and leaves the cell.
Once outside the cell, Litefoot tells Jago and Quick that he pretended to be a part of the Darkling Façade in order to gain her trust. But he reveals that Patsy had in fact told him nothing! He cheerfully then tells Quick that Patsy will be of no more use and suggests having her sedated for her own good. Despite there being missing barrels somewhere on the streets of London, Jago and Litefoot don’t seem too bothered and decide to return to their homes to rest…
Outside the hospital, Litefoot hails a cab to take them to Jacqueline’s Wharf. Jago asks Litefoot what he really learned from Patsy…
Later, the Infernal Investigators arrive at Jacqueline’s Wharf and quickly find the lockup containing the barrels. However, Old Tom arrives and asks what they’re doing. Both men tell Old Tom that they are checking on the barrels while Patsy is ‘indisposed’. Old Tom however is more interested in his payment, so Litefoot invites Old Tom inside the lockup so that they might discuss business.
Inside the lockup, Old Tom begs the investigators about his payment. But Jago insists that they check to make sure these are the barrels in question. He prises one open with a crowbar and sees the amniotic fluid glowing brightly. But he and Litefoot want to make properly sure that it is the fluid. They look at Old Tom and grab him. Old Tom tries to wrestle his way out of their grasp, but Jago and Litefoot dump him into the barrel and infect him with the fluid while laughing sadistically at their efforts…Jago and Litefoot are truly agents of the Darkling Façade…
At the mental hospital, the hospital doctor prepares to sedate Patsy with help from Quick, as per Litefoot’s instruction. Patsy struggles and doesn’t make it easy, so the doctor uses a small dose of sedative to calm her down enough for Quick to talk to her.
At the Red Tavern, Jago and Litefoot congratulate themselves on a job well done. Ellie comes over to offer the pair a drink, but is taken aback when they only ask for a glass of water each…
After the sedation, Patsy seems relatively calm and normal again. She complains to Quick that she can’t hear the voices in her head from the darkness and that it made her do terrible things. She reveals that she told Litefoot everything when he came into her cell. Quick is confused as Litefoot told him that Patsy had said nothing. Patsy repeats everything she told Litefoot to Quick before passing out from the sedative. Quick now begins to have doubts about Litefoot’s credibility…
At the Red Tavern, Jago and Litefoot are discussing steam trains when Ellie arrives with their glasses of water. She quickly leaves the two alone but moves not too far away so she can eavesdrop on them as she is starting to believe her friends are acting strange. Jago and Litefoot begin discussing a plan, unfortunately Ellie can’t hear much as a nearby customer is coughing loudly. Once they stop talking, Ellie returns to their table to find the Infernal Investigators have disappeared. She calls a young street urchin over and offers him some money if he can summon Inspector Quick to the Red Tavern as fast as possible. Something is wrong with Jago and Litefoot…
Jago and Litefoot are walking the streets of London back to the lockup to see if their hired helper has loaded the barrels…
Quick meets with Ellie at the Red Tavern. He states he wanted to meet with Litefoot to inform him of Patsy’s condition, but more pressingly why he lied about the whereabouts of the missing barrels. Ellie suddenly pieces the clues together and realises why they were talking about steam trains and boiling liquids…they intend to use a train to spread the amniotic fluid as an airborne contagion! Ellie explains that Patsy went insane due to exposure to the fluid…and it’s got to Jago and Litefoot. Ellie and Quick leave the Red Tavern and head for Paddington Station to track down the rogue Infernal Investigators.
At Paddington Station, Jago and Litefoot are waiting for Old Tom to deliver the barrels of fluid. Old Tom arrives, now completely under the Façade’s thrall, urges the Infernal Investigators to spread the fluid so the world can fall into their embrace. While Litefoot secures the barrels, he instructs Jago to find an attended steam engine and deal with it’s engineer…
At Paddington Station, Ellie and Quick immediately split up to search for Jago and Litefoot. Ellie immediately encounters Jago. Jago elatedly urges Ellie to come and look at the steam engine he’s secured. Ellie tries to leave and regroup with Quick, but Jago tells her that Litefoot may have lost his mind. He explains that Litefoot has a mad scheme involving boiling the amniotic fluid inside the steam engine and spread it like an airborne virus. For her safety, Jago urges Ellie inside a carriage and shuts her inside. Outside the carriage, Jago gleefully reveals his deception and reveals that he is under the influence of the Darkling Façade. He acquired the steam engine by knocking out the engineer and now that Ellie is safely sealed away inside the carriage, she’ll have a close glimpse of the train’s poisonous payload being pumped into the atmosphere as he drives the train…
Quick is directing his officers around the station to look for Jago and Litefoot. Suddenly, an engine’s whistle is heard and Quick sees Jago, Litefoot and Old Tom inside the engine cab as it departs the station. Quick manages to jump onto the back of the carriage containing Ellie as it speeds out of the station. Ellie can’t get the door open to let Quick inside as Jago locked the door, leaving Quick to hold onto the carriage for dear life…
In the cab, Old Tom warns Jago and Litefoot that Inspector Quick is crawling along the roof of the carriages towards the train. He vows to destroy him and climbs out of the cab to confront Quick. With the train speeding up, it won’t be long before they can inject the water from the engine’s tender into the boiler to create the vapour…
Quick calls out to Ellie and tells her he’ll try and gain access to another carriage. Old Tom rushes towards him proclaiming himself to be the Darkling Façade and transforms into a grotesque slug-like creature. He pounces onto Quick and tries to infect him with his saliva. Before he can do so, Quick tries to warn him of the oncoming bridge…but Old Tom is too late to react and he hits the bridge and becomes a bloody smear…
Quick bursts through the glass ceiling of Ellie’s carriage. With Ellie safe, Quick shoulder charges through the carriage door into the adjoining carriage towards the end of the train to confront the rogue Infernal Investigators.
Litefoot tells Jago that the pressure is building inside the engine and the amniotic fluid is almost ready to be sent into the boiler. Jago can barely contain his excitement and looks forward to the results. Suddenly, Quick and Ellie pounce on the Infernal Investigators and pin them down. Litefoot tries to struggle free for the lever to release the fluid, but he unfortunately falls over the edge of the cab. A furious Jago proclaims Quick killed Litefoot, but Quick assures him that he fell into a bush, which would’ve softened his fall. But Jago won’t listen and flies into a rage and attacks his friends. After a brief fight, Quick manages to pin Jago down and handcuff him. The Darkling Façade’s pawns have been beaten.
Jago is confined at the mental hospital and still furious about Litefoot’s death at the hands of Quick. Quick informs him that the hospital doctor will be along soon to sedate him, which should hopefully cure his debilitating madness. Moments later, a familiar doctor enters the cell and Jago immediately brightens up when he realises who it is…Litefoot! Litefoot turns to Quick and holds him at gunpoint, demanding to know where the train is. Quick admits he doesn’t know as he left one of his officers and Ellie to see to it. The mention of Ellie piques Litefoot’s interest and plans to get the information out of her. But Quick assures them that Ellie won’t say anything…
Later, Ellie arrives at the cells and explains everything. After the train was placed into a siding, she was curious about the contents of the train’s tender…and she touched the fluid. Jago and Litefoot are delighted that Ellie is now a part of the Darkling Façade. Ellie suggests that before they break out and try to retake their train to put their plans back on track, they should celebrate. She produces a bottle of brandy and proposes a toast to the Darkling Façade, much to Quick’s reluctance.
Later, Jago and Litefoot are incredibly drunk from the brandy, and can’t seem to think straight. Thankfully, Quick is able to manipulate Litefoot into giving up his pistol. They then decide to discuss how they’re going to get their train back. Ellie confesses that she and the police had burnt the tender with all the fluid inside, destroying it. Rather than frustration or fury…Jago and Litefoot are drunkenly relieved before they both pass out on the cell floor. Quick commends Ellie for the use of brandy to sedate them both and they hope they’ll wake up free of the Darkling Façade’s influence.
The next afternoon, Jago and Litefoot wake up hungover, completely unaware of the night’s previous events and wondering where they are. They look around and realise that they’re inside the backroom of the Red Tavern. Ellie walks in and greets the Infernal Investigators. Jago mentions having a dream of driving a train with Litefoot and an elderly man, but something awful happened to the man. Litefoot thinks it wasn’t a dream… to which Ellie does confirm. Realising the weight of the damage they’ve done, Jago and Litefoot can only feel sorry for themselves. Quick arrives and announces that he’s brought a friend to visit. Both men groan as the loud, shrill voice of Patsy drills into their heads. Her mudlark scent begins to overwhelm the Infernal Investigators and they start to feel sick. Worst of all is that she plans to take care of them both until they completely recover!
A few days later at the New Regency Theatre, Litefoot arrives to visit Jago in his office. Both men confess to feeling guilty about the fate of Old Tom, stating that he wouldn’t have died if it wasn’t for them falling under the influence of the Darkling Façade. Jago isn’t sure about wanting to continue with his life anymore and confesses to Litefoot that he had contemplated suicide by showing him a prop revolver he had stashed away. Jago holds the gun to his own head and begins to say his goodbye to Litefoot. Litefoot urges him to put down the weapon and think for a moment, but Jago pulls the trigger and a loud gunshot rings out…
Litefoot angrily reprimands Jago stating he could’ve killed himself! Thankfully, the gun only contained a blank. Litefoot suggests that they need to take a break from their infernal investigations and informs Jago that he saw an advert for a cruise. Jago agrees that a cruise should do him and Litefoot some good…after all, nothing supernatural could occur on this cruise…right?
