"Legend of Broken Heart Lake Murder Case" (a.k.a. "The Lake Hiren Murder Case") is the sixth case arc in the Files Series of The Kindaichi Case Files.
Tropes include:
- Bluff the Eavesdropper: Kindaichi finds a bugging device after the Mad Artist has fallen victim to the murderer. Afterwards, he stages an argument with the rest of the survivors and walks out of the cabin where he found the bug with the intention of Bluffing the Murderer and tricking said murderer Lured into a Trap.
- Body in a Breadbox: The man with a Briefcase Full of Money is placed inside a refrigerator after the culprit murders him and mutilates his face.
- Briefcase Full of Money: One of the group members always carries a briefcase with him everywhere he goes. It plays the trope straight, as an accidental bump with a table causes his briefcase to be opened unintentionally, sending money flying out everywhere before he gathers the money and stuffs it back inside his briefcase again.
- Brother–Sister Incest:
- The death of the culprit's sibling lover kicks off a Roaring Rampage of Revenge in this case arc, though the fact that they are siblings doesn't come to light until after the case has ended. Based on the flashbacks shown, while the brother was indeed in romantic love with the sister, there's no given indication if his sister felt the same way.
- The same case alludes to another tale of brother/sister incest which made the location of the mystery (the lake where the pair ultimately drowned themselves) particularly bizarre.
- The Cake Is a Lie: And the culprit, being the son of the president of the company behind the development of the Lake Hiren resort and the owner of the travel agency as well, exploits it.
- The lure that the culprit uses to gather his intended targets for the tour is the membership rights to the resort, which is scheduled to open a year later. According to the doctor among the group, who divulges the details about the membership rights to Kindaichi and Miyuki, who are the only people with no knowledge about the membership rights, the estimated worth of the membership rights is 50 million yennote each.
- Upon seeing Miyuki and Kindaichi instead of Miyuki's cousin in the group, the culprit secretly contacts Miyuki's cousin for a private meeting, with the promise of guaranteed resort membership as lure. It works as planned, and the culprit kills Miyuki's cousin after meeting him outside the campground, mutilates his face, and swaps each other's clothes for the Faking the Dead stunt.
- Cannot Tell Fiction from Reality: A dark example. The culprit in the case Itsuki reported ten years ago was a man in his 20's who confused himself with the characters he saw on TV and spent money on surgeries to look like his favorite actors that he saw, until his face began falling apart after years of facial surgeries, at which point he saw himself resembling Jason from Friday the 13th and went on a murderous spree that started with his family and claimed 13 villagers in total before he was arrested.
- Chekhov's Gunman: Miyuki's cousin who had to bail out of the Lake Hiren test group for college make-up exams at the start of the case comes back later in a big way - the killer had called him out to the other side of the lake, whereupon he takes a boat to get to him and promptly murders him, then uses his body to fake his own death to commit the rest of the murders incognito.
- Connected All Along: After Kindaichi interrogates each of the surviving group members late in the case arc, the common grounds among said members clue him in on the culprit's selection of targets: All of the selected group members were survivors of the Oriental Cruise ship that sank in its maiden voyage three years ago, have suffered acute hydrophobia since then, and have S.K. as their Theme Initials. Even without knowing whether the victims had hydrophobia or not, their Theme Initials still fit, and Kindaichi learns from Miyuki that her cousin, who had the same initials as the rest of the chosen group members, was also a survivor of the Oriental Cruise accident.
- Damsel in Distress: Miyuki accidentally sets off a trap set by the culprit during the case progression, which only gets worse when her injury gets infected, and she's left bedridden (and feverish following the infection) until the case ends.
- Dead All Along: The serial murderer in the case Itsuki wrote in his report a decade ago turns out to have died in prison a year ago, as Kenmochi relays to Kindaichi near the end of the case arc.
- "Everybody Dies" Ending: This is the culprit's intention towards everyone being invited for this tour, anyway. He plans to do this with all the survivors from the Oriental Cruise accident whose names had the initials S.K. Since he couldn't figure out which one was responsible for Keiko's death, he was just going to slaughter them all indiscriminately.
- Facial Horror:
- The modus operandi of "Jason" is to viciously slash his victims' faces with an axe until they are virtually unrecognizable. This is so he can pull a Faking the Dead, substituting one of his victims for himself so he can continue his killing spree.
- The murderer in the case Itsuki wrote in a report a decade ago also mutilated his victims' faces with an axe. Unlike "Jason" in the present-day murder case, however, the culprit in the case Itsuki published did so in a twisted attempt to imitate Jason, who was an "idol" to him.
- Gold Digger: The wife of the man with a Briefcase Full of Money married him for money. As she admits to Kindaichi late in the story, she became attracted to her husband-to-be when he was generous with her while they were dating five years ago, but the attraction turned into disappointment because he turned out to be a moneygrubber after they tied the knot, and she goes further by claiming that she would have never got married to him had she known what he was really like. That being said, she still gets everything he owns via inheritance after he becomes a murder victim due to being his wife.
- He Knows Too Much: The Mad Artist in the group is killed once the culprit finds out that he fixed the broken stereo in the main lounge, as keeping the stereo broken is part of his tricks. That being said, he's among the intended victims right from the start anyway.
- Hope Spot: Eiji volunteers to find outside help via the motorboat at one point, but the motorboat returns the next day with his dead body and unrecognizable face. In truth, it's a stunt pulled by Eiji for Faking the Dead so he can continue his murder spree.
- Identical Stranger: Miyuki turns out to look just like Keiko. This spares Miyuki from the culprit's murder spree (assuming her initials not being S.K. alone didn't suffice) and allows her to prevent a Sadistic Choice from taking place late in the case arc.
- It's All My Fault: Due to the culprit acting rather cordial to Kindaichi prior to pulling a Faking the Dead stunt, Kindaichi is left guilt-ridden over his "death" before Miyuki and the doctor talk him out of it.
- Mad Artist: Downplayed with the artist in the group, who doesn't socialize much with others and tends to draw corpses but is otherwise not a bad person, though the "drawing corpses" part freaks others out, and Kindaichi at one point takes offense at him drawing Miyuki at her injured state by telling him to "knock it off".
- Maybe Magic, Maybe Mundane: How the water of Lake Hiren always turns red at around 4:35 P.M. is never truly discovered. While there is a legend regarding the lake itself (and "Hiren" literally means "tragic love", which hints at the tale over the lake), that still leaves the mechanism behind the phenomenon ambiguous.
- NEET: The culprit in the case Itsuki reported a decade ago is a dark example, as he was a 25-year-old man without steady work who was also prone to confusing himself with whichever actor he idolized most, until his face started to fall apart from years of repeated surgeries and he ended up imitating Jason of all people.
- Never Found the Body: The fate of the culprit after the case arc ends.note
- Sadistic Choice:
- In the backstory, the doctor among the group was responsible for Keiko's death when she grabbed onto the lifeboat he was on, only for him to push her away and cause her to drown. At the time, the lifeboat he was on was already beyond its capacity, so that her hanging onto it was enough to make it tilt. The doctor saw pushing her away as an example of Scylla and Charybdis at the moment, for the lifeboat would sink and cause everyone on it to die if she got on it, too. He's been guilt-ridden by his decision since then.
- After the culprit manages to free himself near the case's end, he decides to spring one such choice on Kindaichi by asking him to kill the doctor in the group in exchange for letting everyone else leave alive. The doctor, already guilt-ridden over what he had done, is on the verge of being Driven to Suicide and turning the culprit's axe on himself, before Miyuki manages to diffuse the situation.
- "Shaggy Dog" Story: This serial murder case arc ends up as this trope for both the Lake Hiren resort and the exclusive membership rights to it. Before the case arc took place, the resort was scheduled to open a year later and the membership rights were in such high demand that they were estimated to be worth 50 million yennote each. After the murder case has occurred, the resort becomes closed indefinitely and the membership rights to it are abandoned as well.
- Shout-Out: To Friday the 13th. Both the present-day murder case and the crime report Itsuki wrote ten years ago allude to it, though for different motives.
- Take a Third Option: Discussed for heartwarming effect at the end of the case arc. As Kindaichi and Miyuki talk about the Oriental Cruise accident, they surmise that the culprit probably would have chosen death in order to give Keiko a better chance for survival had he been with her in that situation, before Miyuki asks Kindaichi what he would have done if they were there. Kindaichi's response is to think of a way to save both of them, which may overlap this trope with Bread, Eggs, Breaded Eggs.
- Tempting Fate:
- The man with a Briefcase Full of Money, in his moment of desperate panic after witnessing — alongside everyone else — the bridge being burned down (which creates the Closed Circle effect for all but the culprit) and the drawing of the first murder victim by the Mad Artist afterwards, decides to leave the resort area by himself, claiming that he'd rather die in the woods than staying in wait to be the next victim. He certainly gets his wish when he encounters the culprit, axe and all, as he runs deeper into the woods.
- According to Itsuki, the Oriental Cruise ship he got on for its maiden voyage three years ago had all the latest technology and various amenities few other cruise liners had, which resulted in it being popular enough that people called it "unsinkable aquatic hotel resort", only for it to sink after colliding with an oil tanker.
- The culprit states that he can never part with the wristwatch he wears, as it's a Tragic Keepsake from Keiko that he has in remembrance to her. The case ends with him triggering a bomb blast as he boards the boat; while he's unaccounted for, a panel shows his wristwatch broken from said bomb blast and sinking in the lake.
- Theme Initials:
- A major part of this case; the killer knew that the person he was after had the initials S.K., but not which of the individuals involved was the true target.
- For Kindaichi, realizing that everyone who's been invited to join this group shares the same initials allows him to pinpoint the culprit's identity, as the culprit is the only person besides Kindaichi himself (whose name is Hajime) and Miyuki whose initials are NOT S.K.
- 13 Is Unlucky: The culprit in the article Ituski reported a decade ago committed the murders of 13 people in total before being arrested.
- Too Dumb to Live: Even after the bridge is burned away, which creates the Closed Circle effect, and knowing a serial murderer can be anywhere in close vicinity, the man with a Briefcase Full of Money insists on getting out by himself, which makes him an easy target for the culprit and ends with him being killed. After regaining composure shortly after Kindaichi finds him as a Body in a Breadbox, his wife remarks to herself that he's never been the brightest person she's ever met.
- Tragic Keepsake: The wristwatch the culprit wears turns out to be from Keiko, the girl whose death fuels his Roaring Rampage of Revenge. The culprit admits it outright to Kindaichi that it's the one thing he could never part with him due to it being the only thing he has in remembrance to her.
- Wanting Is Better Than Having: This case arc begins with Kindaichi being informed by a male classmate of his that he had sex during the summer... but he's not feeling all that excited now that it's done.Once it was done, it wasn't that big of a deal.
- Wham Shot: The photo of Eiji and Keiko that Itsuki presents to Kindaichi and Miyuki is a two-fold example.
- On the front, it shows that Keiko is an Identical Stranger to Miyuki, which explains why Miyuki is spared from Eiji's target list and could talk him out of instigating a Sadistic Choice.
- On the back, the caption indicates Keiko was Eiji's younger sister, marking Eiji's romantic feeling towards Keiko as an example of Brother–Sister Incest, at least on Eiji's part.
- Why Did It Have to Be Snakes?: This is an Exploited Trope in this Case, as all of the intended targets in this case have suffered acute hydrophobia after surviving an accident three years ago following the collision between a cruise liner they were on and an oil ship, where they nearly drowned. The culprit has a boat at the ready in case the need to get away arises, counting on the targets' hydrophobia to prevent them from using the boat.
