Spoilers follow for the complete bombing case and the Mary storyline through this two-part episode. The old man’s identity is discussed as a theory, not a reveal.
The Hotel Serial Bombing Case (Part 1) and The Hotel Serial Bombing Case (Part 2) are international episodes 1202-1203 (Japanese episodes 1144-1145). They adapt Volume 103, Files 1094-1096: A Coincidental Meeting, The Three Codes and The Secret of the Square.
The bomber is the hotel bellboy, Kureishi. His intended victim is Hayashizaki, whom he also tries to frame for the earlier bombings. Conan exposes the deception and Mary prevents the bomb from operating; nobody dies in this case. The elderly man using a respirator belongs to a separate, unresolved thread involving Mary.
Those two levels of resolution should stay separate. Identifying the bomber does not identify the old man, and the man in sunglasses who acts after the arrest is not revealed as the bomber’s partner. His intervention changes what Mary can keep hidden rather than reopening the solved bombing.
Sera’s invitation has an antidote agenda
Masumi Sera approaches Conan at a bookstore in Haido and has him open a bottle of carbonated water. Her behavior suggests that she is testing his movements and possessions. She then uses the ciphers from the hotel bombings to invite him to the hotel where she and Mary are staying.
Mary waits out of sight in Sera’s room. The pair want access to Conan’s antidote, but Conan has some understanding of their purpose and has not brought it. Their attempt fails on this occasion, while the underlying desire to obtain the drug remains.
Mary also worries that being exposed and having to move again could bring trouble upon an unnamed person. That suggests a connection extending beyond the mother and daughter, but the reference does not identify the person or establish the exact form of any assistance.
A new cipher turns the visit into an emergency
In neighboring Room 2114, Hayashizaki argues with hotel cleaner Moriko Ronda. A new cipher is found in his room. Kureishi joins Conan and Sera as they head to reception, and a call purporting to come from the bomber gives them until 5 p.m. to answer the code.
Eri Kisaki is present as the hotel’s legal adviser. She helps obtain the earlier ciphers and deal with the situation, bringing practical authority to Conan and Sera’s investigation. The codes initially narrow the possible location to six rooms.
Three people emerge as suspects: Hayashizaki, Ronda and Kureishi. Hayashizaki looks particularly suspicious because the previously bombed hotels had banned him. It seems easy to read the attacks as retaliation for those disputes, but that connection has been chosen to mislead investigators.
The cipher points to the intended victim’s room
The three messages use a rail-fence cipher. The square-enclosed Japanese syllabic characters are linked to letters on a keyboard, and arranging the letters in the indicated pattern reveals room numbers. The sequence resolves to Rooms 3420, 2614 and 2114.
The third number identifies Hayashizaki’s room as the present bomb location. That shifts his role from an apparently plausible bomber toward a person being targeted. Mary intervenes to prevent the device from operating, allowing the effort to stop the explosion and the hunt for the culprit to proceed together.
The tension comes from making the cipher answer actionable. It is not an isolated word puzzle: it determines which room contains the danger before the deadline arrives. Eri’s help, the detectives’ reasoning and Mary’s intervention all have different roles in protecting the people inside.
The humidifier exposes a false claim about access
Kureishi says he has not entered Hayashizaki’s room. Yet he knows the position of a humidifier placed there at short notice. That knowledge contradicts his account of where he has been and makes an apparently ordinary staff remark incriminating.
He had an opportunity to duplicate a key after Hayashizaki dropped it. He used a soap impression to make a spare and entered before Hayashizaki checked in, placing the bomb and cipher in Room 2114. His access is therefore central to both the physical attack and the story he constructs around it.
The bomber’s phone call is a performance
The threatening call does not respond naturally to Conan’s questions. That failure matters because the voice is recorded. Kureishi uses recorded audio and multiple smartphones to create the appearance of an outside bomber calling at the right place and time.
Kureishi also tries to make it appear that a phone will be thrown from the rooftop. Conan instead predicts that he will act from a room directly above or below Room 2114 and waits for him there. The interception blocks his attempt to dispose of evidence and completes the exposure of the phone deception.
Conan incapacitates Kureishi with his tranquilizer device, and the police take him into custody. The clues work in sequence: the cipher identifies the room, the humidifier contradicts his denial of entry, the unresponsive voice exposes the recording, and the anticipated movement allows Conan to intercept him.
Why Kureishi wanted to kill and frame Hayashizaki
Kureishi is a cannabis dealer. Hayashizaki uses the drug, knows about Kureishi’s dealing and threatens to expose him unless he sells it more cheaply. Kureishi responds by planning to kill the man who holds that leverage over him.
The earlier attacks target hotels that had banned Hayashizaki, creating an apparent revenge motive for him. The final attack is meant to eliminate Hayashizaki while preserving that false explanation. The series of bombings is therefore a carefully constructed frame surrounding a personal attempt at silencing him.
Hayashizaki survives. Calling this a completed murder would erase the success of Mary’s intervention and Conan’s capture of the culprit. The blackmail explains the grievance but does not excuse a plan that endangers an entire hotel.
Why the final alarm appears aimed at Mary
After the arrest, a man in sunglasses activates an emergency alarm. Mary and Sera leave the hotel, and the elderly man with a respirator sees Mary outside. The alarm is an additional intervention after the bombing case has already been solved.
The early glimpse of someone following Sera, including the black shoes later associated with the man in sunglasses, connects this movement to the closing scene. Sera’s whereabouts were already accessible to him. Watching her speak to someone inside and then prompting an evacuation suggests that the less visible Mary is the person he wants to expose.
The old man responds as though he is seeing something dreamlike. One possible reading is that he recognizes Mary from her adult life and is startled by her present appearance. That would explain his reaction, but recognition of her adult self remains an interpretation of the scene, not a stated identification.
Does that reaction rule out Renya Karasuma?
The old man also appeared in Momiji Ooka’s Sweet Trap (Part 1) and Momiji Ooka’s Sweet Trap (Part 2), international episodes 1193-1194 (Japanese episodes 1135-1136). This later encounter supplies a new clue about his interest in Mary without resolving who he is.
One argument against the Renya Karasuma theory is that genuine surprise at a younger Mary might suggest unfamiliarity with the de-aging effect of APTX 4869. If the observer already expected that effect, a different reaction might seem more natural. It is a reasonable question to raise, but it depends on assumptions about both his knowledge and his sincerity.
The scene does not prove that he is ignorant of APTX 4869, and it does not rule Karasuma out. Nor does it establish that Karasuma has taken the drug himself. A reaction that sounds astonished is evidence to interpret, not a complete record of what someone knows.
Why Yasuharu Haneda is a plausible alternative
Yasuharu Haneda has a substantive connection to the Akai family. After Koji Haneda’s death, Tsutomu Akai was asked to investigate. Yasuharu and his wife also adopted Shukichi Haneda in connection with the ambition Koji had been unable to fulfill. Those relationships give the Haneda theory a basis beyond the observer simply being an older man.
The earlier investigation request is relevant background from The Antique Tray Can’t Be Hidden (Part 2) and The Antique Tray Can’t Be Hidden (Part 3), international episodes 1076-1077 (Japanese episodes 1019-1020). It supports a family connection; it does not by itself identify the man at the hotel.
A possible reconstruction is that Yasuharu remains in contact with Mary but has not been told about her changed body, and that her refusal to appear has made him seek a direct look. Mary’s concern about involving an unnamed person could fit that reading too. Each additional step remains hypothetical: this episode confirms neither the continuing contact nor the identity of her unnamed connection.
Yasuharu is therefore a plausible candidate, not the confirmed answer. The ending’s power lies in how little the observer has to do: the bomb has been stopped and the culprit arrested, yet one look at Mary leaves a new threat or connection unresolved. The case closes cleanly while her ability to remain unseen does not.
Comments