AI: The Somnium Files Wiki
AI: The Somnium Files Wiki

Day 5: Tuesday -ihAI- (5日目:火曜日 -遺灰-, 5-Nichi-me: Kayōbi -ihAI-, lit. Day 5: Tuesday -Ashes-) is a chapter featured in AI: THE SOMNIUM FILES.

It is the fourteenth and final chapter of the Annihilation Route. It covers Kaname Date's interrogation of the New Cyclops Killer.

Case File Synopsis[]

In Boss's Somnium, Date witnessed the New Cyclops Serial Killings; a bizarre, twisted cycle in which the killer became the next victim.

The person in Boss's mind was So's son, Saito. He was the New Cyclops Killer. Date also discovered that his body originally belonged to Saito. Saito demanded his body back, using a bomb strapped to Hitomi as leverage. The body exchange occurred, and "Saito," back in his original body, detonated the bomb on Hitomi while Date in Boss watched helplessly. Date's consciousness allowed him a few words before vanishing completely...

Story Summary[]

ABIS HQ, Tuesday[]

Interrogation Room, Tuesday 3:14 AM[]

Saito's interrogation.

Date, having realized the truth about the New Cyclops Serial Killings, confronted Boss about the murders. He realized that the killer had used the Prototype Psync Machine in the abandoned Kabasaki Chemical Plant, and the person in front of him was not really Boss. Date recalled a memory of Pewter explaining that the Psync System was capable of swapping bodies. He explained that the killer had been in the bodies of Shoko Nadami, Renju Okiura, Iris Sagan, So Sejima, and Boss, using each person's body to kill the previous one. The killer, realizing Date knew the truth, stopped pretending to be Boss, and admitted to the murders.

The killer identified himself as Saito Sejima, the son of So Sejima and his late wife. Saito confirmed that he had been in Iris's body during her interrogation on Sunday. When Date said he imitated her well, Saito explained that when swapping bodies with the Psync Machine, a small fraction of the original body's memory remained. Using those remaining memories, Saito could imitate their mannerisms and remember certain details the host knew. Saito asked Date why he knew about the prototype Psync Machine, speculating that he was regaining his lost memories. Date disagreed—he remembered Iris telling him that parallel worlds existed.

Date asked Saito to explain how each of the murders were committed. On Friday, Saito was in Shoko's body. He called Renju around 4:00 PM to meet with him at the chemical plant. There, he put Renju to sleep, swapped bodies, and stabbed Shoko's body to death with an ice pick. Around 8:00 PM, Saito drove the body to Bloom Park using an abandoned subway line, tied the body on one of the horses, and sent a NILE message to Mizuki asking her to come to the park.

On Saturday, as Renju, Saito called Iris around 5:00 PM to meet him at Sunfish Pocket. She arrived around 6:00 PM, and Saito asked her to come with him to the chemical plant. He put her to sleep on the drive there, swapped bodies, and strangled Renju's body with a rolled-up apron. While driving back to Sunfish Pocket with the body in the trunk, Ota spotted him driving Renju's car alone in Akihabara. Saito told Ota he was running an errand for Renju, and asked him to keep it a secret, since an idol driving without a license could damage her career.

On Sunday, as Iris, Saito went to Lemniscate to record the podcast Iris was scheduled to record, then encountered Date in the lobby. Saito, not wanting to draw more suspicion, complied with the interrogation and the Psync. Afterwards, he asked Date to drop him off at Marble, hoping to find a chance to run. During the drive, Ota messaged Iris, and Saito took the opportunity to ask for his help. After Ota knocked Date out, the two left in the van, until Saito asked Ota to stop to buy a drink. While he was out of the car, Saito took it and drove to the Sejima Residence. So let him inside, and Saito told him he needed to show him something. Eventually, So agreed, and got into the van. They arrived at the chemical plant around 11:50 PM and swapped bodies.

After midnight on Monday, as So, Saito took Iris to the Okiura Fishery Cold Storage Warehouse. He arrived around 1:00 PM to prepare for the stream. Ota arrived unexpectedly, so Saito stabbed him with the kitchen knife and put Ota into the polar bear costume. He left around 3:30 AM.

Later on Monday, Saito used a secret So and Boss shared from six years prior to get in contact with her. Saito put her to sleep, brought her to the chemical plant, and swapped bodies once more. After shooting So's body and cutting it into pieces, Saito put the pieces in a large vase and brought it back to the mansion.

Date asked Saito additional questions about the murders. The victims' left eyes were removed because it was required for the prototype Psync Machine to work. Instead of replacing the eyes, Saito disposed of them by eating the eyeballs. Saito also explained a special feature of the prototype—it would administer a sedative to his previous body and a stimulant to his new one, preventing the victims from resisting. When asked about why the bodies were displayed the way they were, Saito told Date it was to harass him. He called Mizuki to Bloom Park and streamed Iris's murder for the same reason, deeming them important to Date. Saito told him that the murders were a form of revenge against Date.

When asked what he meant by "revenge," Saito explained that he thought of the murders as a journey, traveling through the victims' bodies to finally reach his home—Date's body. Saito told Date he had stolen his body from him six years ago, and he wanted it back. Saito's original brain would release a flood of dopamine and endorphins when he committed murder, and he had not been able to experience the same happiness from killing in anyone else's body. Date protested, saying that he did not have Saito's oxytocin deficiency, but Aiba informed him that she supplemented it regularly. Date had believed #89 to be the Original Cyclops Serial Killer, but Aiba realized they had misunderstood Pewter's explanation. #89 did not have Saito's consciousness, but rather Rohan Kumakura's.

Hitomi held hostage.

Date and Aiba attempted to work out the specifics of the body swapping, using Saito as a starting point. Before Boss, Saito had been in So Sejima's brain, then Iris, Renju, and Shoko. Saito confirmed that he had been in Rohan's body before Shoko's, until one year ago. He had lost most of his memories, and was housed in a mental hospital. Over time, he slowly regained his memories, left the hospital, and found Shoko. He swapped bodies with her, leaving her in Rohan's body, who panicked and committed suicide upon realizing what happened to her. Over the next year, Saito spied on Date and developed his plan. Before Rohan, Saito had been in his original body. Date was confused about who his personality originally belonged to—he had been in Rohan's body, meaning #89's body was originally his.

After explaining everything, Saito demanded his body back. Pewter ran in with a laptop showing a live feed of Hitomi with bombs strapped to her. Saito asked for his body in exchange for Hitomi's location, which Aiba was unable to trace. Reluctantly, Date agreed to Psync with Saito.

Psync Room, Tuesday 4:28 AM[]

Saito after the Psync.

Date and Saito successfully switched bodies with the Psync Machine. Date, now in Boss's body, demanded to know Hitomi's location. As promised, Saito told him she was at Boss's house, but moments later, the bombs detonated, killing Hitomi. Date attemted to run after Saito, but collapsed due to Boss's broken leg. Before Saito could leave, however, Aiba knocked him unconscious with a paralyzing shock and jumped out of his eye socket towards Date. As Aiba called out to him, Date wondered if he could have had a better future, and blacked out.



  • The name ihAI (遺灰) translates to "Ashes," which is in reference to the explosion that kills Hitomi Sagan at both the normal and bad endings. It could also be symbolic to the tone and themes of the chapter, as the villain, Saito Sejima, has won and achieved his desired victory, leading into the worst possible outcome in the game.


Kaname DateAI-Ball/AibaIris Sagan/A-setOta MatsushitaMizuki OkiuraBossPewterNew Cyclops Killer
Hitomi SaganMayumi MatsushitaRenju OkiuraMamaShoko NadamiSo SejimaMoma KumakuraRohan KumakuraCyclops Serial Killer
#89FalcoBodyguardsTakero MatsushitaManaka IwaiSaito SejimaYakuza AYakuza BNurseReceptionistMermaidTaxi DriverInspector
Chiyoda District: Police Headquarters (Boss's Office; Psync Room; Interrogation Room) • Sunfish Pocket
Koto District: Harbor Warehouse District (Cold Storage Warehouse) • Date Residence
Meguro District: Sagan ResidenceTiefblau
Minato District: Sejima ResidenceKumakura OfficeIkume ShrineLemniscateCentral Hospital
Near Kabasaki District: Bloom ParkOld Chemical PlantMatsushita Diner
Shinjuku District: Golden Yokocho (Marble)
Other: Fuchu City (Fuchu Prison) • Akikawa ValleyOkutama MountainsEitoku High
SINKIN' IN THE BRaiN (Spoiler) • PSYNCIN' IN THE PaiN (Spoiler)
PSYNCIN' IN THE VaiN (Spoiler) • PSYNCIN' IN THE SWaiN (Spoiler)
PSYNCIN' IN THE VILLaiN (Spoiler) • PSYNCIN' IN THE MaiN: 1 (Spoiler)
PSYNCIN' IN THE MaiN: 2 (Spoiler)
Red Route: sigAIsaikAImeikAIsyokubAIrihAI
Yellow Route: syougAIseisAIhiAIsanpAI
Green Route: gumAIjukkAIkikAIjinnAIihAI
Purple Route: keitAIgyoukAIkyuusAIsyuurAIirAIdakkAIkekkAI
Pink Route: kenzAIjutAIkokkAIsousAIhakAIkassAI
Tokyo Metropolitan Police Department (Advanced Brain Investigation Squad) • Ujisaki Family (Kumakura FamilyKumakura Estates) • Secret Society NAIXATLOZForeign Mercenaries
LemniscateSunfish PocketMarbleTiefblauFamiSto8-12Elgorg
Wadjet SystemEvolverLight Synaptic Nerve Connection DeviceDate's CarShovelForgeOdoroki-man ChocolateGeostationary Satellite X00639
Chemical Plant ExplosionOriginal Cyclops Serial KillingsBreak-In at Sagan ResidenceNew Cyclops Serial KillingsIncident at Minato District HighwayDisappearance of Renju OkiuraOperation: Iris Rescue
Full List of Events