Isaac: What a crazy day, <Player's Name>! We don't get giant apes running amok in Concordia's streets every day, that's for sure!
After being informed by Chief Wright that a giant ape had escaped from its enclosure and now was rampaging through the city, Isaac and the player rush to the animal's cage to look for clues regarding its whereabouts. There, they find the cage wide open and the poisoned body of Professor Ernest Picklebrain, the scientist behind the giant ape's growth.
Tropes:
- Attack of the 50-Foot Whatever: A giant ape named Kiki the size of a big house rampages through the city in this case.
- Big Damn Heroes: Rose does this twice regarding the giant ape: first, she subdues her with a dart gun, allowing Kiki to be safely retrieved and put on her cage, and later calms her down before another rampage happens by singing her a lullaby that puts Kiki to sleep.
- Bioluminescence Is Cool: Subverted. Both Somerset and his sister Aurora think that what Picklebrain's experiments did to her (make Aurora glow in the dark) are a curse that ruined her life, and it's also the reason why Somerset killed him.
- Buffy Speak; When Dick informs you that Picklebrain was killed with a Chironex fleckeri jellyfish, Isaac calls it a "Chiro... flex... something".
- Call-Back: Mayor Cornelius Castletown and Katherine Woolf reappear as suspects. Eleanor Halsted (also seen in the same case as them), Greta Gundwood, and Lady Highmore also reappear during the Additional Investigation.
- Death Faked for You: Somerset Osborne lies about the death of his sister Aurora since she's gone hiding because of her condition, claiming that she died years ago. However, you find her well and alive during the Additional Investigation.
- Escaped Animal Rampage: Kiki the giant ape goes on a King Kong-esque rampage at the start of the case, destroying part of Century Mile in the process.
- Excrement Statement: Willie Conklin, Kiki's caretaker, put some of her excrement of Prof. Picklebrain's hat as a revenge for his mistreatment and being a Mean Boss to him.
- Find the Cure!: A portion of the Additional Investigation focuses on finding a cure for Aurora's glowing problem. Though not a permanent one, Dick manages to find a remedy that, as long as she keeps ingesting it, will stop making her glow in the dark.
- Force Feeding: The victim was killed by being forced to ingest a jellyfish after getting knocked out by the killer.
- Going for the Big Scoop: Katherine was trying to interview Prof. Picklebrain regarding the giant ape because she hadn't gotten an exciting story ever since Mr. Alastor, going as far as harassing Picklebrain much to his annoyance. She later gets her story after the case is solved by interviewing Aurora, who was also experimented by the professor.
- Guest-Star Party Member: Katherine Woolf joins you during most of the Additional Investigation to help cure Aurora of her glowing disease, as she's Going for the Big Scoop and believes interviewing Aurora after helping her will provide one good story.
- King Kong Copy: Kiki the giant ape. She even climbs up a building during the main investigation, although this one's a copy of the Eiffel Tower rather than the Empire State.
- Mad Scientist: Apart from making a normal-sized ape grow to gigantic proportions, Picklebrain also did unethical human experimentation, such as somehow making Aurora permanently glow in the dark. Coupled with many others experiments is what led Somerset to murder him.
- Mad Scientist Laboratory: The victim's laboratory (which he shared with another less mad scientist) appears as a crime scene, which is also where the killer got the jellyfish from.
- Mean Boss: According to Willie, Picklebrain used him as a punching bag whenever his experiments went wrong and also docked his pay for months for no reason, which is why Willie decided to take revenge by putting ape feces in the professor's hat.
- Motherly Scientist: Compared to Picklebrain, Dr. Beata Seahorn is less mad and more caring towards the animals she works with, even calling the jellyfish used to kill him "her baby".
- Pet Monstrosity: Willie Conklin, Kiki's caretaker, actually sees her as a pet instead of one of Picklebrain's experiments, giving her a name and remaining preoccupied for her well-being throughout the case.
- Pet the Dog: During the Additional Investigation, you, Katherine, and Dick help Aurora recover from her glowing condition by finding a remedy, fixing her life after years of hiding due to Picklebrain's experiments.
- Phosphor-Essence: Aurora Osborne, Somerset's sister, literally glows in the dark as a result of the victim experimenting on her, although you manage to find a remedy to help her after the case is solved.
- Sabotage to Discredit: After some Foreshadowing in the previous two cases, this one confirms that there's a saboteur tampering with the World Exhibition's inventions when Charlie and Greta find proof of foul play on Greta's color camera, meaning that Celine's Chessmaton and Orville's Steampack were also messed with.
- Shout-Out:
- Willie Conklin is named after Wilkie Collins.
- Kiki the giant ape is an obvious parody of King Kong.
- William Shakespeare is quoted in Chapter 1.
- Sticky Fingers: Dr. Seahorn accuses Prof. Picklebrain of being this, claiming that he always took her instruments without permission and even labeled them as his property.
- Tap on the Head: Both Picklebrain and Willie were knocked out by the killer, the former so he could be forced to ingest the jellyfish that killed him and the latter so Kiki could be released from her cage.
- Tested on Humans: As it turns out, the victim experimented on animals and humans alike, something that made Somerset see him as a monster and therefore kill him.
- Tranquillizer Dart: Rose uses three of these to subdue Kiki and capture her during the main investigation.
- Uninvited to the Party: Mayor Castletown had uninvited Picklebrain to the World Exhibition due to seeing his ape experiment as a waste of time and not that interesting compared to the other more useful inventions.
- Unwitting Test Subject: Judging by how she hates glowing in the dark, it's clear that Aurora did not wanted to take part on Picklebrain's experimentation that led her acquiring said condition.
- Urban Ruins: A section of Century Mile (which you also investigate) is rendered to this after Kiki's rampage causes some destruction on the streets.
- We Need a Distraction: Somerset released Kiki from her cage as a distraction so he could murder Prof. Picklebrain and divert attention from the police.
- Wealthy Philanthropist: Somerset Osborne is a socialite and also a science benefactor who donated money to Picklebrain's experiments, although he obviously regretted it once the professor decided to experiment on his sister.
