Recap / The Kindaichi Case Files Seiren Island Murder Case

"Seiren Island Murder Case" is the twelfth case arc in "The Kindaichi Case Files R" series of The Kindaichi Case Files.

After seeing the flyer promoting a fishing tournament, Kenmochi, a fishing enthusiast and a professional fisherman during his younger years, signs up for it, and Kindaichi, upon discovering that the winner in said fishing tournament would be rewarded 200 million yen^note  (about $2 million in USD) and each participating group can have up to three people, eagerly signs himself and Miyuki up as Kenmochi's assistants in the hope of having a share in said grand prize. Together, the three of them reach Seiren Island, where the fishing tournament is set to take place, along with some others, in anticipation for the tournament. Before the tournament can advance, however, they find themselves entangled in a serial murder case.

---

Tropes include:

• Amicable Exes: Downplayed. The culprit divorced with his then-wife, who got sole custody of their daughter, and they didn't contact each other for years due to each of them living their separate lives. When he met his daughter and started bonding with her, his ex-wife took a neutral stance by contending herself with keeping a close watch without interfering, though they still didn't interact with each other. It was only after their daughter died that they talked to each other, over the circumstances leading to their daughter's demise.
• Bitch in Sheep's Clothing: More than one in this case, as the team of doctors turns out to be this. While they present themselves to be life-saving healthcare professionals on the surface, in truth they subject many a patient under their "care" as Unwitting Test Subject and write off the deaths of those from their tests via deflective means while utilizing Manipulative Editing to keep up their helpful facade, and the culprit's motive centers around them — with the intent to sue them at first before the revelation about his own daughter causes the culprit to decide to murder them instead.
• Censored Child Death: The death of the culprit's preteen daughter as an Unwitting Test Subject by the doctors who were supposedly "treating" her cancer is not shown.
• Connected All Along:
  • The cameraman in this case arc had previously worked with the group of physicians in the past. A brief discussion ensues upon his reveal of this work-related history.
    Miyuki: B-But they didn't show any reaction when they saw you!
    Cameraman: We cameramen always bring our camera so our faces are almost never seen, and we rarely exchange card info.
  • The culprit and the elderly island resident turn out to have known each other when the former was once an inhabitant of the island before leaving with his family.^note  It's quite possible, even though it's never outright stated, that the culprit was much younger when leaving the island, which would explain why the elderly island resident never shows any signs of recognition towards the culprit until nearly the end of the case arc.
    Elderly island resident: I didn't realize since your surname has changed.
    Culprit: My parents got divorced after I left this island. The surname I carry now is my mother's after she remarried.
• Dangerous Windows: The culprit deliberately invokes this by making an intended victim, who's unconscious at the time due to having unwittingly consumed drinks that have sleeping drugs within, sit close to a window while setting up a series of reactions from objects that would end with a lethal blow to the target via an underwater rifle shooting an arrow straight through the glass door that leads to the patio outside.
• Death of a Child: The culprit's preteen daughter dying in the hospital where she was treated for cancer drove the culprit into investigating the truth behind her demise, which, after the culprit discovered it, became the motive behind the serial murder case in this arc.
• Destroy the Evidence: The culprit confesses to have destroyed the recording device that contains the statement given by one of the doctors regarding a preteen girl (who, unbeknownst to the would-be victim, is the culprit's own daughter) being an Unwitting Test Subject of theirs after said doctors left, which helped to signal the culprit's change of focus from suing the doctors to murdering them.
• Due to the Dead: As the elderly resident informs Kindaichi and Miyuki after the serial murder case is wrapped up, the metallic item that's located at the bottom of the island cave, which is relevant to the serial murder case in this case arc, is the only remaining submarine of Kaiten, Japanese suicide navy crafts that were developed in the last stages of WWII. Being stranded underneath the island in rehearsal during wartime, it has been left alone since then, with all island residents at the time deciding to keep it a secret from outsiders in an attempt to memorialize those who were essentially wartime Human Sacrifice themselves.
  That Kaiten submarine is one of the memories I have of this island, because that thing is an eternal gravestone to memorialize many of the kamikaze soldiers, whose lives were seen as nothing much and only amounted to be sacrifices in the war.
• Dying Town: Seiren Island is technically "dying island", as the island has no separate townships itself, but the trope applies all the same because it has a dwindling human population. At the present day, there's only one person, an octogenarian woman, who's still residing on the island. According to her testimony that's relayed to Kindaichi and Miyuki, the island population was around 100 in her younger years, during and after WWII, but the failed attempt to turn the island into a resort after WWII caused the already-critical economic status of the island to become downright unsustainable, which, in turn, resulted in the continual decrease of the island population until only she herself remained as its inhabitant, which has held true for the past twenty years.
• Hypocritical Humor: After the island resident manages to catch and cook some fish after two people have become murder victims, Kindaichi gripes about the lack of appetite... while helping himself with the fish.
  Miyuki: They seem so delicious, but I feel like I have no appetite!
  Kindaichi: [with his mouth full of fish] Like there would be an appetite in this condition!
• Impaled with Extreme Prejudice: The first murder victim is killed when the culprit stabs him In the Back with a spear that penetrates through his heart and pokes right out of the chest.
• Informed Ability: The participants in this case arc are supposedly experts in fishing — most of them, at least, as Kindaichi's fishing skills are just basic enough to grant him rudimentary knowledge and Miyuki, by her own admission, doesn't even know "how to set a bait to the fish". Due (in part) to the serial murder case derailing the fishing tournament to the point of it being canceled, the viewers never get to witness any of the participants showing their fishing expertise. The only person who manages to catch fish in this case arc is the elderly resident, but she uses an underwater rifle in conjunction to the diving gear to catch fish because she admits to being too old to have the strength that's needed to fish via a fishing rod, so she doesn't count.
• In Vino Veritas: In this case, alcohol served to make the intended target a Loose Lips. The culprit states in his confession that one of the doctors told him about the truth of a grade school girl being an Unwitting Test Subject that died from their experimental drug while she was under their "care" while he was having drinks with them one night for business as a sales representative and the other doctors were away at the time. It was this revelation that would soon drive him to murder.
• Leaning on the Fourth Wall:
  • An exchange between Kenmochi and Kindaichi early on in the case arc alludes at the many times they find themselves in a bad place that would take center stage for a murder mystery.
    Kenmochi: Seems like we've come to a very horrible place, haven't we, Kindaichi?
    Kindaichi: Not like it's the first time...
  • After two people have died, an exchange between the mystery novelist and the accompanying editor goes like this:
    Novelist: Who do you think the culprit could be?
    Editor: Eh? The first case was a murder, but wasn't the second case only an accident?
    Novelist: Nonsense! No accident would happen right after a murder occurred! Just like in a novel, this must be a serial murder case!
  • As Kenmochi has summoned all of the survivors for Summation Gathering, the mystery novelist has this to say:
    In the mystery novel, this would be the climax!
• Manipulative Editing: In-Universe. As the cameraman accompanying the TV producer confides to Kindaichi, Miyuki, and Kenmochi late in the case arc after the entire team of doctors has died in the murder case, said doctors appeared in a medical TV show in order to promote anti-cancer medicine developments that they worked on. While they gave off the impression that they were serious about developing such medications on TV, in truth they would check recordings, cherry-picking only parts of the recording that showed them in a good light while cutting off any parts that didn't show the tests run by them as successful, including when an Unwitting Test Subject died after being subjected to such tests, which the cameraman discovered by accident.^note  This testimony clues Kindaichi and Kenmochi in as the motive for the murder case at once, as they believe that there may have been many who fell victim to the team of doctors and that the culprit likely has been related to one of them. Indeed, the culprit confesses near the case's end that his own preteen daughter was one such victim.
• Mayor of a Ghost Town: For all practical purposes, the elderly octogenarian woman serves this role on the island, being the only one to inform others (fishing enthusiasts, for instance) about the environmental layout and the history of the island, after everyone else has moved away.
• Most Writers Are Writers: One of the participants in this case arc is a mystery novelist.
• Only in It for the Money: Kindaichi has himself and Miyuki signed up in Kenmochi's team in the fishing tournament solely because the grand prize for said tournament is 200 million yen^note  (about $2 million in USD) and he hopes to have a share in it. That ends up not working out due to the tournament being canceled altogether because of the serial murder case taking place where said tournament would commence.
• Outliving One's Offspring: The culprit and his ex-wife lost their only child to the team of doctors who treated her (and many others under their "care") as Unwitting Test Subject.
• Papa Wolf: The culprit's motive for the serial murders stems from his daughter being subjected as an Unwitting Test Subject and dying from it. His lamentation at the end of the confession is also focused solely on his deceased daughter.
  Even though I've done all this, my daughter won't come back to me.
• Playing Possum: As Kindaichi reveals in The Summation, the culprit pretended to be the first murder victim after killing said victim In the Back. No one was suspicious because 1) everyone had the same outfits because it was right at the moment of the scheduled fishing tournament, 2) the murder itself took place around 4 A.M. when sunrise had yet to take place, decreasing natural visibility as a result, 3) the culprit pulled the head cover of the outfit over his own in imitation of the victim to conceal his face and turned off the lights in the room he was in at the time to prevent anyone from being able to see his body more clearly, and 4) the culprit managed to rejoin everyone else without his brief absence being noticed during the ensuing panic to reach the room where the murder victim was.
• Read the Fine Print: The island event organizer and the TV producer who are in charge of the fishing tournament had the participants sign a contract with the caveat that absolves the organizers of any and all responsibilities should any accidents occur on the participants themselves while the organizers themselves chose days with particularly bad weather to hold the fishing tournament in an attempt to boost viewer ratings.^note  Not that it matters anyway, first because the ferry that carried everyone to the island already left and won't arrive for the next several days, which, combined with the stormy weather condition that makes rowing a boat out to sea downright dangerous, makes the island itself a Closed Circle, and then the serial murder case taking place on the island causes the whole tournament to be canceled altogether in its wake.
• Rube Goldberg Hates Your Guts: The culprit murders one of the doctors via a series of chain reactions from objects he sets up while he himself joins everyone else, in order to avoid having to manually deal the killing blow on the victim, who's unconscious due to having consumed drinks laced with sleeping drugs, thereby to prevent suspicion being cast towards himself.
• "Shaggy Dog" Story: The winner of the fishing tournament would have been given the grand prize of 200 million yen^note  (about $2 million in USD), which Kindaichi hopes to have a share in and is the only reason he has himself and Miyuki sign up in Kenmochi's group, only for the tournament to be canceled because of the serial murder case, something Kindaichi laments after the case concludes.
• Slain in Their Sleep: One of the victims is done in via a series of chain reactions that are designed to kill said victim on purpose while the victim is asleep due to the culprit Slipping a Mickey beforehand.
• Slipping a Mickey: The culprit places some sleeping drug inside the drinks for one of the victims, causing said victim to eventually fall asleep inside her own cabin, which allows the culprit to set up the scene to make it possible to get said victim killed while also permitting himself to join everyone else at the scene of the murder without having to pull the trigger manually.
• Soft Water: When Kindaichi, Miyuki, and Kenmochi decide to investigate the cave on the island while it's raining heavily in search of potential clues about the serial murder case, Miyuki and Kenmochi secure a rope that Kindaichi holds onto as he climbs down, but his foot slips at one point due to the rainwater rendering the rocks more slippery, resulting in him falling a distance... into seawater, which leaves him none the worse for wear.
  Kindaichi: At least I'm saved. If I were to land on the rocks, I would have been dead for sure!
• Sticky Situation: Played for Drama, as the use of adhesive is employed as part of the culprit's murder plot for one of the victims, which Kindaichi states during The Summation.^note  To elaborate: The culprit had secretly placed small capsules containing strong and quick dry glue that would break when pressed with strong enough force inside the victim's gloves — they were designed with tightening lock — and fishing rod in advance. Then the culprit raided the food storage and emptied the food contents before anyone arrived, manufacturing a food shortage and creating mass panic, which, in turn, necessitated fishing in a stormy weather for food. The intended victim, who had built up a bit of reputation as an expert fisherman who managed to catch fish in bad weather, promptly volunteered to catch fish — that, too, was what the culprit had anticipated beforehand. As the victim started fishing, the culprit, having already known where the intended victim would show up to fish, arrived secretly without anyone else being aware of his whereabouts before he, while underwater, took hold of the fishing line and tied it to the jet-propeller diving equipment the culprit used for diving, at the same time pulling the thread slightly to make it seem as though a fish had bitten the lure, in order to wait for the glue in the gloves and the fishing rod to dry due to the gripping force being applied to them releasing the glue. Upon making sure the glue was completely dry, the culprit started the jet-propeller equipment, pulling the victim underwater, fishing rod and all, and the victim couldn't let go due to the glue in the tools. All that remained for the culprit to do involved keeping the victim underwater long enough to drown, which the culprit was able to manage due to having proper diving equipment, including an oxygen tank with more than enough air supply to outlast the victim, and the deed was done.
• The Straight and Arrow Path: An underwater rifle that fires sharp needles is utilized in this case arc.
  • The culprit uses it in the design for a series of chain reactions that would cause lethal result on the intended target without having to manually pull the trigger in order to avoid suspicion.
  • A bit earlier, the elderly island resident is seen using it to hunt for fish, as she states that her advanced age has sapped her the strength that is required to fish via fishing rod.
• This Is Unforgivable!: The culprit outright said this after stomping on the recording device he carried that contained incriminating evidence that the doctors he had been investigating privately had treated many patients under their "care", including his own preteen daughter, as Unwitting Test Subject, signifying his change of role into a Vigilante Man.
  UNFORGIVABLE! THEY SAW MY DAUGHTER AS A MERE GUINEA PIG! I'LL KILL THEM ALL, AS I WOULD CRUSH AN INSECT!
• Unwitting Pawn: Kindaichi discloses during Summation Gathering that the invitation letters that are supposedly penned by one of the victims actually were written by a young, female stranger instead, before everyone arrived on the island for the scheduled fishing tournament, and that whoever penned said letters most likely did so under the pretext of a part-time job without knowing what the letters were intended for at all.
• Unwitting Test Subject: The murder victims in this case arc are doctors who supposedly treat cancer patients but actually subject many a patient under their "care" as guinea pigs for some experimental drug they develop without their patients or anyone related to said patients being informed of this. The most extreme example of this, as the culprit reveals in his confession, involved his own preteen daughter being subjected to such a drug only to die from it, and it was the discovery of the truth behind this particular case that drove the culprit into deciding to murder them instead of merely suing them.
• Worth It: When Miyuki watches the oceanic view around them as the ferry is carrying the fishing tournament participants to Seiren Island, the oceanic wind blows hard enough to lift her skirt and enable Kindaichi to cop a Panty Shot, with Kindaichi excitedly calling the oceanic wind "kamikaze"^note  ("divine wind" in Japanese). Miyuki promptly punches Kindaichi square in the face, though his remark makes it clear that he considers her punishment an acceptable price to pay.
  Miyuki: (irritated) You saw it, didn't you, Hajime-chan?!
  Kindaichi: An honorable death for kamikaze...
• Yank the Dog's Chain: As the culprit states in his confession, his daughter was very young when he and his wife divorced, and he didn't see them again for a few years afterward, but a chance encounter with his daughter while he was relaxing at a playground in a park on one Sunday caused his daughter to start bonding with him every Sunday hereafter. Even though she didn't know he was her father and no one told her the truth, he enjoyed their time together all the same and his ex-wife contended herself with keeping a close watch without interfering. All of this came to an abrupt halt when his daughter stopped showing up there altogether, and his ex-wife met him several weeks later before she tearfully told him about their daughter being admitted to a hospital for cancer treatment before dying there. The short time span between their daughter's admittance into the hospital and her death, combined with her healthy appearance prior to being admitted there, raised a red flag in him, a professional medical researcher himself, and so he requested the Human Resources department to transfer him to the Sales department in order to investigate the truth behind her demise^note  — in secret, that is, as he confided to no one about his real reason for such a request prior to his confession toward the end of the case arc.