Megure, Takagi and Chiba arrive at the karaoke box to investigate. They reveal that the name of the deceased is Tatsumi Moniwa and that he has suffered several fatal blows on the head. Since nobody has left the karaoke box since Moniwa’s arrival, the police is able to determine that the murderer has not escaped, and thus one of Eisuke, the clerk, Konji Arimoto, Kunio Tamai and Kyota Honma (the last three people are all customers arriving after Conan and company, and they do not know each other). Upon seeing Arimoto and his companion (who never left the room and thus not a suspect), Eisuke becomes horrified and starts sweating again, which prompts Sonoko to ask him (impatiently) what the matter is. Eisuke stammers for a while, but eventually is able to find the courage to answer Sonoko’s question: he points at the very muscular Arimoto, and swears that he saw him make out with his companion, who is also very muscular. Sonoko, Ran, Conan, Megure and Takagi are all petrified by this account, and Takagi says that if the ones kissing were a normal couple then he would be fine with it, but in this case it was between two men. Arimoto’s companion angrily storms out of their room at this moment and accuses Takagi of being disrespectful, as she is actually a woman, just very muscular, sounding masculine and having short hair.
After this small incident, the police return to the case. By looking at the footage captured by the security camera, they see that Homna was the first one to get out of his room after Moniwa had gone into his; Homna walked towards Moniwa’s room, but according to him only because the toilet is there. Then Eisuke went to the same place, then Arimoto, then Tamai, who says that he went to the vending machine beside the toilet and not the toilet itself. Finally, the clerk and Conan went in that direction (the time difference is about one minute); since Conan says that the blood was dry when he got to the crime scene, the clerk is then definitely not the murderer.
The police then search the personal belongings of the four remaining suspects to collect more clues and to, hopefully, find the murder weapon, as they have not found anything reseambling a murder weapon anywhere else. Despite a detailed search, no valuable clue is found (at least the police believe so), much to their disappointment. Conan is puzzled as well, and while he brainstorms Chiba comes to Megure with the photos that Moniwa had taken before death: all of them are centered around Sonoko, forcing Conan to reconsider his assumption that the deceased is an FBI agent and not a stalker. At around the same time, there is a breakthrough in the murder case as well: Conan is inspired by Arimoto’s mention of poker cards, and all of a sudden he knows who the murderer is and what object he used in order to deal the fatal blows.
Conan tranquilizes Sonoko and begins his deduction. He says that the reason that the police were not able to find the murder weapon is that it changed shape and disappeared after achieving its purpose. On hearing this, Takagi deduces that Tamai is the murderer, because he has an insulated container in which he can store a huge chunk of ice. Conan says that Takagi is wrong, because the chunk of ice is bound to break apart after hitting a person’s head repeatedly, but there are no fragments of ice in Moniwa’s room nor is there anything watery. Megure also gives his opinion: he deduces that the murder weapon must be Arimoto’s bottle of soft drink; Arimoto just needs the content of the bottle to be frozen in order to have an effective weapon. Conan is let down again; he says that since the bottle was full, there was not enough time for all of it to melt in the period between the murder and the police’s belonging search. The true murder weapon, Conan reveals, is coins; more precisely, a large number of coins piled on each other in a sock (sock is, for some reason, known as “black jack”, which is also the name for a card game). Conan says that he is able to think of this by noting a subtle change: in the time period between the murderer (Kyota Honma)’s accidential entry into Conan’s room and the present, his left boot abnormally enlarged, meaning that he had put on an extra sock on his left foot (the police ususally do not check boots and therefore will not discover a blood-tainted sock). As for the coins, Honma could get rid of them easily by buying things in the vending machine. In this particular case, Honma bought a large amount of cigarettes, as one of his personal belongings is a huge pack in which there are numerous cigarette cases. Conan explains that he definitely did not buy the pack as a whole (this is what Honma claimed) because all the cigarette cases inside the pack would then have the same production date; this is not the case. Another piece of evidence is that Honma once said to the police that “even if I have met the victim, which I have not, it must have been in the corridor or in the bathroom (and definitely not in Moniwa’s)”. Since Moniwa’s given name (Tatsumi, or 巽 in the native form) is used by both males and females, and the bathrooms of the karaoke box are separated according to gender, Honma’s words suggest that he personally knew the victim. However, he told the police that he did not.
Honma, unable to explain why he lied on several occasions and knowing that the police are about to search for fingerprints on the coins in the vending machine, knows that he has been exposed. He angrily admits that he does know the victim, as he was the kidnapper of his son, and killed the 4-year-old boy when Honma contacted the police. Megure says that he knows which case Honma is talking about; he further reveals that the police knew that Moniwa was behind it, but had to drop the charges due to a lack of evidence. Honma remarks that there was no evidence because the police failed to notice Moniwa’s trick (but he eventually did, and used it to kill Moniwa).
With the case solved, three highschoolers and Conan go back home. On the way, Eisuke remarks excitedly that he is impressed by Sonoko’s deduction; Ran agrees, saying that her performance was as good as Shinichi’s. Eisuke therefore asks whether they are talking about Shinichi Kudo, and Sonoko immediately affirms, and adds jokingly that Shinichi is Ran’s husband, but is not currently living with her because he is dealing with a complicated case. Ran blushes and objects as usual, and Conan changes the subject by saying that he wants to head back to the bookstore before returning home. Eisuke follows him, explaining that he wants to ensure Conan’s safety.
Conan sees right through Eisuke’s lie and asks him what he wants to discuss in private. Eisuke tells him that he has decided to go to the United States. Conan asks whether that is because he accepted the witness protection program, and Eisuke says (as Conan expected) that he has rejected that, and that apparently the Black Organization did not notice him at all. Eisuke then says that the real reason behind this decision is that he wants to become a CIA agent and continue his father and elder sister’s work. Conan comments (without saying anything out loud) that unless Eisuke fixes his carelessness problem the CIA will not accept him (at this very same moment Eisuke slams his chin on a utility pole); and he enquires curiously why Eisuke would bother to come back to Teitan High School if he will leave soon. Eisuke says that this is his chance to confess to Ran; he recounts that he fell in love with Ran at first sight, as he had never known such a gentle girl. Eisuke carries on by saying that the problem is that Ran seems to like Shinichi Kudo; given this, he wants Conan to contact Shinichi to ask for his opinion on whether Eisuke can confess. Eisuke vows that if he is with Ran, he will never abandon her (unlike Shinichi), and will instead take her with him to the United States and give her happiness. Upon hearing this, Conan says solemnly that Eisuke cannot (confess); the latter responds that he is asking for Shinichi’s opinion, not Conan’s. Conan thus reiterates his objection to Eisuke’s confession.
Eisuke thus has made Conan admit that he is Shinichi. To Conan’s surprise, Eisuke is not startled by this fact, but instead laughs out loud. Eisuke explains that since he initially thought that Rena Mitsunashi and Kogoro Mouri were “bad guys” who had colluded and hidden his elder sister, he did some research on Kogoro, and found that his deductive abilities always underwent a dramatic change after entering “sleeping Kogoro state”. He further found that Conan always appeared alongside sleeping Kogoro, and that the rise of sleeping Kogoro roughly coincided with Shinichi no longer attending school. In other words, Eisuke knew who Conan was from the beginning (but he does not know why Shinichi shrank into a child, nor does he seem interested in this matter). Eisuke also claims that he left a hint to Conan (which Conan completely overlooked); specifically, during his first visit of the Agency, he deliberately bumped into Conan and, with his eyes closed, greeted Conan by saying “Hello, Detective Mouri, this is the first time that we meet…”.
Conan now realizes that everything that Eisuke has said a moment ago was part of a well-designed plot to force him to reveal the truth. Eisuke agrees, but says that his feelings towards Ran are genuine, and that he wants Conan to make her happy. Eisuke then mentions that something seems to have happened to the FBI; Conan acts as if he knew nothing about this, and Eisuke does not insist on asking. In the last panel, Conan thinks to himself (with a confident smile on his face) that something did happen, but that everything will be fine.
The arsonist is Ginya Makabe. Due to his flat being completely burned down, Subaru Okiya is offered by Conan to live at Shinichi's house, since the Kudo family is away at the moment. Subaru will also be able to work his PhD with Agasa. Conan seems to act in a strange way with Okiya, and Ai notices it. That night, alone in the house, Subaru is seen drinking Bourbon.
The culprit is the bike delivery woman. The press dubbed her 'Hammer man', and people took it for granted that the culprit's gender was male, despite that none of the victims had identified the gender of their attacker. Moreover while the man who borrowed the apartment was a man, he did bring his girlfriend over. So the person was the one, who left, while the girlfriend stayed in apartment. The culprit had taken away the underwear and socks to hid her gender, and since Conan could only find one pair of shoes with a shift-pad, which is used in driving a motorbike, they must belong to the real delivery man, who was found in the apartment. Since the woman didn't take her victim's shoes with her, she will probably not try to escape on the motorbike, but instead change her clothes in a public toilet to avoid witnesses. She has also knocked out the pizza man to make him the police's the prime suspect. But Shiratori caught her in time. Her motive is resentment toward her ex, who left her and started dating long-haired women. After a witness followed her back to the apartment, she decided to pin her crimes on her ex, but the police survelliance spoiled it.
The culprit is Maiko Kuzumi. She committed suicide after the murder by jumping off Nakame's flat's window. Shogo Somei found her corpse and got what happened due to a last text message from her, saying she did it to help Somei out, since Nakame was exploiting him shamelessly. Somei decided to hide her corpse in his car's trunk, and went up to Nakame's, rearranging the plates and things to have police believe Nakame was alone and only killed himself.
