Jago and Litefoot have been summoned to Buckingham Palace by The Colonel. While waiting for The Colonel, Jago excitedly wonders what infernal mystery he has assigned for them. Litefoot however tries to caution his friend’s excitement stating that they don’t exactly go looking for danger. The Colonel greets the two men and asks the investigators to remind him why they have been under Queen Victoria’s employ. Litefoot responds that Her Majesty had heard of their adventures dealing with seemingly paranormal affairs that threaten The British Empire and to an extent – the world. Jago however is eager to receive his new assignment, but The Colonel informs them that Her Majesty would simply like a report from the two men regarding every instance they’ve dealt with the supernatural. Litefoot is understandably hesitant to divulge such information, but The Colonel assures him that it is for the security of The British Empire so they can be ready to strike back against any form of threat. Even so both men show reluctance to talk, but The Colonel reveals that he is aware of at least one villain Jago and Litefoot have battled – Dr. Tulp and his Mahogany Men. Jago lets slip that he and Litefoot have also fought ghosts and werewolves to name a few. The Colonel wishes for Jago and Litefoot to focus more on the cases that have more plausible explanations – in particular Dr. Tulp. Litefoot explains that the battle he and Jago had with Dr. Tulp was a rather long time ago and they can’t give an exact recount of the events that transpired at the very moment. The Colonel understands and gives the two men three days to produce a report on Dr. Tulp - in particular his technological feats and deliver it to him. The Colonel promptly takes his leave and warns the two to be ready for when he sends a carriage for them, as they don’t want to disappoint Her Majesty. Litefoot is offended by The Colonel’s veiled threat and suspects that something else is going on that he isn’t aware of. Jago however is starstruck by Her Majesty taking an interest in his work and oblivious to The Colonel’s particular interest in Dr. Tulp.
That evening, Jago and Litefoot visit The Red Tavern, where they meet with Ellie Higson. The two men sit down to drink, while Ellie converses with a rather upper-class woman at the bar whom she knows isn’t a regular. The woman reveals to Ellie that she is actually here because of a man. Ellie immediately cottons on to the implication and promises to keep her supposed secret safe. Meanwhile, Jago is salivating at the prospects of fame now that his and Litefoot’s adventures are of knowledge to Queen Victoria. Litefoot however is not convinced and believes that The Colonel is hiding something. Furthermore, he noticed that after they left Buckingham Palace, a cab followed them. Jago chalks up Litefoot’s suspicions to nerves and recommends that he orders another pint, and so he calls Ellie over to take their orders. The two men confide in the barmaid about their suspicions of being followed and Ellie recommends they speak with Sergeant Quick. With that said, Litefoot decides to meet with Quick the next day to see if he and the Sergeant can find any information in regard to The Colonel.
The next morning, Litefoot meets with a weary Sergeant Quick at the police station. Quick apologises for his tiredness as he had been dealing with multiple cases of ‘shredded corpses’ that have cropped up all over London with seemingly no pattern between each victim. Unfortunately, there have been no leads as to who could’ve done such grisly deeds. Nonetheless, he discards his troubles and offers his assistance to the Professor. Litefoot requests Quick to keep his request under wraps and begins to explain his suspicions about the enigmatic Colonel…
At the Regency Theatre, a messenger called Mr. Drucker arrives to deliver a message to Jago from the Colonel. Jago is immediately excited at the prospect of a new assignment, but the messenger simply states ‘The Colonel would like to remind Jago and Litefoot that asking questions can be very dangerous…’ and requests in particular that Litefoot receives the message as the Colonel is aware that he has been investigating him. Jago seemingly understands the underlying threat in the messenger’s words and promises to relay the message before bidding the visitor a good day.
Later that evening at the red Tavern, Jago relays the message to Litefoot. Jago was very aware of the threat behind the words and Litefoot is offended by the message. Nonetheless, it confirms Litefoot’s suspicions about the Colonel as his investigation with Sergeant Quick revealed very little about the mysterious man – not even a mention of a Colonel being appointed an officer within the Queen’s Palace. Jago however tries to hold onto the possibility that being a high ranking official, the Colonel must keep an air of secrecy. But Litefoot continues by revealing that his contacts within the government have stated that the Colonel doesn’t hold as much sway as he lets on and has shown a great interest in industrial manufacturing, plus he has also spent a considerable amount of money purchasing the notes of the mathematician Charles Babbage. This finally wins Jago over to Litefoot’s side, but the question is why is the Colonel showing interest in the pair of them and what interest does a military officer have in manufacturing? Jago reminds Litefoot that they are to meet with the Colonel at the Palace the next day, but Litefoot advises Jago that they should make excuses to avoid the Colonel until they know what they’re dealing with…
Ellie arrives at the table and jokes about how the two men are missing out on all the fun, especially in regard to a rather attractive patron called Agatha. Litefoot is curious as to why a woman of Agatha’s social standing is hanging out in a pub like the Red Tavern. Ellie almost slips out the possibility of a gentleman being involved before scurrying off…
Jago and Litefoot leave the Red Tavern for the evening. Litefoot reminds Jago that they have agreed to turn away the Colonel’s summons when they arrive. With that said, both men go their separate ways into the streets.
Jago walks along a darkened street, but can’t help but feel as though he is being followed. He initially chalks it up to the alcohol and resumes walking, but immediately becomes paranoid and demands the mystery stalker to show themselves. Unfortunately, Jago is attacked and restrained by a woman at gunpoint. The woman, revealed to be Agatha from the Red Tavern, informs Jago that she is an agent of Queen Victoria and has orders to arrest him for conspiring with The Colonel. Jago denies working with the Colonel and angrily denounces his name and that he and Litefoot are currently trying to investigate the Colonel themselves. Agatha doesn’t believe him and namedrops Shingle Cove as one of many possible missions he and Litefoot have aided the Colonel in his bid to threaten the monarchy, as well as the fact that just after they left the pub, Litefoot was seen conversing with two of the Colonel’s thugs. Horrified, Jago rushes past Agatha, fearing for the Professor’s life. Surprised by Jago’s resolve to save his friend, Agatha begins to believe Jago’s side of the story and offers to aid him in rescuing Litefoot.
Elsewhere, Litefoot is approached by two of The Colonel’s thugs, Drucker and Mayhew. The two thugs attempts to intimidate Litefoot fall flat, but nonetheless inform him that they wish to take him for a ride to meet with The Colonel. As if on cue, a horse drawn carriage pulls up alongside the group. Litefoot refuses to cooperate with the thugs and tries to leave, but Drucker informs him that they didn’t exactly give him such an option. To ensure Litefoot’s capture, The Colonel has provided the thugs with one of his ‘special friends’ to persuade the Professor. The carriage doors open and a sound of mechanical whirring and clunking emits from within. A robotic soldier emerges from the carriage armed with a large cannon. Drucker proudly introduces the machine as one of the Colonel’s foot soldiers or ‘Sentinels’, a fully autonomous weapon. Drucker gleefully demonstrates the Sentinel’s weaponry on an innocent bystander, who is blown to smithereens by the devastating weapon, much to Litefoot’s disgust. He instantly puts two and two together and deduces the Sentinels are behind the spate of dead bodies cropping up over the city, to which Drucker confirms and explains that the Sentinels have to get target practice somehow. Drucker once more coerces Litefoot to take a ride with them to meet the Colonel, to which Litefoot resigns himself to do seeing as he no choice anyway.
Jago and Agatha hear the sound of the Sentinel’s weapon and fear for the Professor’s safety. Agatha deduces the sound was emitted close by. They turn a corner and see Litefoot with the Colonel’s thugs, much to Jago’s relief. But their relief is short lived when they witness Litefoot being forced into the carriage with the Sentinel’s weapon trained on him. Jago urges Agatha to help rescue Litefoot, but Agatha advises against doing so as they are clearly outmatched with the Sentinel in the thugs possession, especially when she sees the remains of the Sentinel’s victim from earlier. She advises that she and Jago should allow the carriage to depart and they will follow close by to see where it leads, then call for reinforcements. The two give chase, but Jago proves to be quite unfit in comparison to Agatha, who fears they’ll lose the Professor if she continues with Jago. Much to Jago’s reluctance, she advises Jago to return to the Red Tavern and await further instructions from her while she continues the chase.
Jago, out of breath and coughing up his lungs, bangs on the door to the Red Tavern. Ellie shouts that she is closing up for the night, but nonetheless opens the door to find Jago waiting for her. Seeing the terror on his face, she invites him inside and prepares a whiskey (At Jago’s request for his nerves as he claims). Jago explains how Litefoot was kidnapped by the Colonel’s thugs and assumes that they were probably after the pair of them for prying into the Colonel’s identity and plans. He reveals that Agatha is actually an agent for Queen Victoria trying to bring down the Colonel and that she instructed him to wait at the Red Tavern for instructions. Ellie is more shocked by one of her new regulars being a spy more than anything and joins Jago in downing the whiskey.
The thugs carriage eventually comes to a stop outside a factory. Drucker leads the Professor out of the carriage and leads him inside. Litefoot is shocked to see a whole army of Sentinels being mass produced. Drucker and a squad of Sentinels lead Litefoot inside the factory to a cell, where Drucker tells Litefoot that the Colonel will talk with him soon. Before locking him up, Drucker leaves a Sentinel on duty to make sure Litefoot doesn’t try to escape.
Jago wakes up after passing out from drinking too much whiskey. Ellie shows him a note that had been slipped under the cellar door from Agatha. The note states that she was able to track the carriage to a factory in the dockyards. The factory happens to be under a false name and is actually one of the Colonel’s fronts for his Sentinel productions. She orders Jago to meet with her at the factory so they can mount a rescue for Litefoot. Ellie questions Jago on whether or not they should really trust Agatha, especially considering that she originally believed Jago and Litefoot to be agents of the Colonel. Jago explains his initial encounter with Agatha and how he managed to convince her otherwise. Besides, she is the only hope and lead they have to rescuing Litefoot. Ellie eventually agrees to accompany Jago on his mission and the two prepare to head for the docks.
A few hours later, Litefoot is rudely awakened by Drucker, who informs him that The Colonel is on his way to question him. Moments later, The Colonel enters and callously tells Litefoot that he should be grateful he hasn’t had him killed. The Colonel orders Drucker to leave but allows one Sentinel to stay. The Colonel informs Litefoot that he will answer his questions or he will order the Sentinel to kill him, to which the Sentinel raises it weapon at Litefoot. Litefoot however remains defiant and tells the Colonel that he won’t get any information out of him if he’s dead. He realises that the reason the Colonel sent them to Shingle Cove was not to investigate the ghostly apparitions, but to ensure that they didn’t interfere with his experimental warship. Litefoot demands to know who The Colonel truly is. The Colonel obliges and explains that he was in fact a former Colonel to Queen Victoria up until recently. The British Empire is incredibly powerful but lacks ambition for the future. He plans to use the Sentinels to overthrow Queen Victoria, then expand and conquer the rest of Europe, reclaim America and install himself as Emperor. He reveals that the Sentinels are powered by probability calculations or ‘The Babbage Engine’ (named in honour of Charles Babbage) that assess situations and can act accordingly to their military directives. Litefoot sadly concludes that the Colonel is completely insane and can’t be reasoned with. But he asks what the Colonel’s plans for world domination have to do with Jago and Litefoot. The Colonel laughs darkly and states that he simply employed the Infernal Investigators so they may divulge the secrets of their former enemy – Dr. Tulp and his mahogany men. The Sentinels are fine killing machines but a few refinements in their programming courtesy of Dr. Tulp would make them near unstoppable. The Colonel gives Litefoot 24 hours to give up the secrets of Dr. Tulp or he will order the Sentinels to kill him. Litefoot refuses to say anything, but the Colonel then decides that Jago may be more cooperative under duress and sets off to capture him.
Outside the dockyards, Jago and Ellie hide amongst the bushes. They hear the sound of bushes bristling, Jago assumes it to be Agatha and calls out quietly only for the noise to belong to a Sentinel. The Sentinel marches towards their hiding place, despite not seeing the two trespassers, but nonetheless, Jago and Ellie decide to retreat.
Once they manage to get away, they are confronted by Agatha, who assumes Jago received her message. Agatha apologises for her deceptive behaviour, but states that she couldn’t simply state her true mission of spying on Jago and Litefoot in hopes of finding the Colonel. She states their mission is to rescue Litefoot from the factory, but also find a way to disrupt the mass production of the Sentinels. Agatha plans to cause a distraction while Jago and Ellie sneak into the factory via the waterways and rescue Litefoot. Once Litefoot is safely extracted, they should all reconvene at the Red Tavern. Unfortunately, Agatha underestimated the number of Sentinels patrolling the dockyard and its subsequent passages. Even more unfortunate, before they can split up and carry out their individual missions, a Sentinel sneaks up from behind causing the three to abandon their hiding place and split up. Ellie unfortunately comes face to face with Drucker. Drucker immediately calls for a squad of Sentinels to his position. Ellie is surrounded by the robotic soldiers and taken away to be interrogated by the Colonel.
Drucker shoves Ellie into a cell in the factory, the same cell currently being occupied by Litefoot. The two are glad to see each other again, but Litefoot chastises Ellie for putting herself in danger. Drucker is sure that Ellie isn’t alone, but assures her the Sentinels will hunt them down…
Outside the factory, Jago and Agatha are eventually cornered by the Sentinels. In an act of bravery, Jago stands up to one of the Sentinels and demands that it lower its weapon…which to Agatha’s surprise, it does and upon Jago’s orders, turns to leave. Unfortunately, it returns momentarily to harass them again and Jago goes on a hyperbolic rant for it to leave them alone, even going as far as pouring the remaining whiskey into it, causing it to start malfunctioning and eventually explode. Agatha deduces that the Sentinel is programmed to obey simple orders, but Jago’s extensive vocabularic rants confused it and caused it to explode. Simply, the Sentinels are incredibly stupid intellectually. Agatha points out the doorway where Ellie was taken, but there are a lot of Sentinels standing between them. She has a plan to get through, she needs Jago to talk more over the top nonsense to the rest of the Sentinel army to confuse and destroy themselves. Jago agrees to do so and the two set out their rescue mission.
Jago steps out of hiding and calls out to several Sentinels in the vicinity. He orders them to lower their weapons and begins to speak an alliterative filled speech of nonsense to the machines. As Agatha deduced, the machines begin to spark and explode from confusion. Fortunately, the confusion spreads to other Sentinel squads around the dockyard and they all start to explode. Jago is proud of his achievement in destroying an army of killer robots with just his words, but his victory is short lived as the Colonel shows himself. The Colonel is furious that his work has been set back by several months and threatens to end Jago’s life for his meddling. Agatha jumps out of hiding and pounces on the evil terrorist, much to Jago’s shock as a gunshot rings out…
Inside the factory, the effects of Jago’s confusing speech has reached the machines inside. Drucker, Ellie and Litefoot look on in shock as the machines fizzle with sparks before eventually one of them explodes in Drucker’s face, killing him instantly. Ellie proudly states that this is all the efforts of Jago and Agatha. With the machines self-destructing, Ellie states that they must get away while they can. The Colonel’s mechanical monstrosities have gone up in smoke…
The next morning, the doorbell to Litefoot’s house rings. Litefoot answers the door to find Sergeant Quick waiting for him. Litefoot assumes he is visiting to discuss the matter of the dockyard or of the whereabouts of Jago and Agatha as they didn’t regroup at the Red Tavern as planned. He invites the Sergeant inside, who confirms he has news of their whereabouts. Quick’s voice is solemn and shaky as he states that he and his men found a body at the dockyards earlier in the morning, but it wasn’t the Colonel…but of Henry Gordon Jago. Litefoot is silent upon hearing about the death of his best friend. But unfortunately, Quick has more news to tell. He simply states that he has a job to do and orders to follow. His voice full of regret, Quick announces that he arresting Litefoot on suspicion of murdering Jago…
