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

Day 4: Monday -youdAI- (4日目:月曜日 -容態-, 4-Nichi-me: Getsuyōbi -yōdai-, lit. Day 4: Monday -Condition-) is a chapter featured in AI: THE SOMNIUM FILES.

It is the ninth chapter of the Red Route. It covers Kaname Date's investigation of the the attempted murder of Iris Sagan and Ota Matsushita.

Case File Synopsis

Monday at dawn, while hunting down Ota, Date received a call from Boss. The culprit was live streaming! Panicking, Date watched the video: Iris was lying underneath an ice-cutting machine...

Ota heroically saved Iris's life, but was stabbed by the culprit, whose identity was hidden with a polar bear costume. While investigating, Date discovered that Ota's mother, Mayumi, suffers from a kind of dementia. He also confirmed that the Odoroki-man chocolate he found was purchased by Mayumi. But why? Date visited Ota at the hospital to ask some follow-up questions. Ota revealed that Iris was driving Renju's car Saturday night. But he was covering yet another secret... He had a fruit knife hidden under his blanket.

Story Summary

Driving, Monday ~2:50 AM

Iris about to be cut in half.

Aiba explained to Date how Ota knocked him out, and showed him the footage she recorded afterward, in which Ota left Matsushita Diner with Iris. Boss called to inform Date of a livestream the New Cyclops Killer was broadcasting. Iris, with her left eye missing, was chained to the workbench of an ice-cutting machine. Date hurried to Okiura Fishery Cold Storage Warehouse, the video's source. During the drive, Ota appeared on camera and turned the machine off.

Cold Storage Warehouse, Monday 3:17 AM

Ota bleeding on the ground.

Date arrived at the warehouse to find Iris, unconscious but alive, and Ota, bleeding from a stomach wound. Ota told Date that the culprit left through the back door, so Date went to pursue them.

ABIS HQ, Boss's Office, Monday 9:34 AM

Boss at her office.

Date returned to ABIS after being unable to catch the culprit. Boss informed Date that Ota and Iris were both in the hospital, and Ota's surgery had been successful. Mayumi had gone home to bring things to Ota for his hospital stay, and Hitomi was still waiting at the hospital. Aiba explained that Okiura Fishery was founded by Renju's father, but Renju himself never owned the company. Date left ABIS to investigate the crime scene and speak to various persons of interest.

Harbor Warehouse District, Monday - Free Move

The police stationed in front of the Warehouse.

Outside the warehouse, Date and Aiba examined the two cars parked outside. One, the Matsushita family van, had Ota's fingerprints on the steering wheel, and Iris's fingerprints around the passenger seat. Ota's cell phone was also inside under the driver's seat. The other car was a stolen station wagon. Ota stole the car at 10:33 PM on Sunday from the parking lot of a FamiSto.

Okiura Fishery Cold Storage Warehouse, Monday

The interior of the cold storage warehouse.

Date and Aiba investigated the interior of the warehouse. The laptop and camera used to stream could not be traced back to the buyer, and the WiFi password was written on the router, meaning anyone could have used it. No fingerprints were found anywhere, and the ice-cutting machine did not appear to have been brought by the culprit. In the corner of the room, Date found a package of Odoroki-man Chocolate using Aiba's night vision mode.

Matsushita Diner, Monday - Free Move

Mayumi's family photo.

Date found Mayumi looking at a photo of her family, and asked her several questions. She explained that Ota used to collect Odoroki-man chocolate stickers as a child. When Date asked about Mayumi's husband, Aiba informed him that he died five years prior; however, Mayumi still believed he was alive. She also seemed unaware that Ota was in the hospital, or that she left the diner on Sunday night. Aiba's thermal scan of Mayumi revealed that she had low blood flow in part of her brain, indicating that she suffered from dementia. Aiba also revealed that Matsushita Diner had been closed for eight years, since the chemical plant explosion.

Sejima Residence, Monday - Free Move

So Sejima at home with his bodyguards.

So Sejima and his bodyguard were unwilling to provide any helpful information. So insisted that he was at home sleeping the previous night, but Aiba discovered that all the security cameras in the mansion were turned off, making it impossible to prove. So denied knowing Iris, and would not elaborate on his relationship with the Kumakuras. After the bodyguard threatened Date, Aiba's x-ray vision revealed that he was carrying a gun, but Date was unable to do anything without a warrant.

Hitomi at the hospital.

Central Hospital, Monday - Free Move

Hitomi was resting in one of the hospital rooms. She told Date about how she lost her friend, Manaka Iwai, at a young age, and thought about her while Iris was in surgery. She also explained that Ota had been one of her students, and she felt grateful to him for protecting Iris. Hitomi also said it was unlikely that Iris knew So, and told Date she was at home at the time of the incident.

Date Residence, Monday - Free Move

Date with Mizuki at home.

Date apologized to Mizuki for leaving her behind at Marble, telling her he did not want to endanger her by bringing her into a yakuza den. Date told Mizuki that Ota and Iris would both live, and asked Mizuki about Okiura Fishery. Her explanation matched the information Aiba provided about the company. She also told a story about her grandfather being raised by dolphins.

Mizuki after being bullied.

Before he left, Mizuki asked to come along on the investigation, insisting she was strong enough. Date remembered when he first trained Mizuki to fight. One day, Mizuki returned from school after being bullied by her classmates. Date decided that he needed to teach her how to defend herself.

Ikume Shrine - Flashback

He began training her in martial arts at the Ikume Shrine, but he soon discovered that Mizuki had incredible physical strength, almost superhuman.

Driving, Monday

Driving towards the Hospital.

Aiba went over the facts of the case with Date. They were unable to find a clear link between So and the case, or Renju and Okiura Fishery. Aiba explained that Mayumi may have seen the culprit, but due to her dementia, may not remember. She also informed Date that Mayumi's fingerprints were found on the Odoroki-man chocolate from the warehouse.

Central Hospital, Monday 5:42 PM

Date and Boss questioned Ota together. Ota said he did not see the person inside the polar bear costume. Ota explained that after leaving the diner, he stopped at a convenience store. While he was out of the car, he heared Iris scream, and saw the van drive away. Ota stole another car in the parking lot to chase after her, but eventually lost track of it. He later realized that his cell phone was still in the van, and used its GPS function to trace its location to the warehouse. There, he fought the polar bear and eventually got stabbed. Ota did not say anything about it, but he recognized the Odoroki-man chocolate from the warehouse. He also did not want to tell Date about "that thing," but after Date insisted he needed the information, Ota said he saw Iris driving Renju's car Saturday evening in Akihabara. Iris asked him to keep it a secret, since an idol driving without a license could ruin her career.

Ota with the knife he hid.

Date used Aiba's x-ray vision to see that Ota was holding a knife under his blanket. Ota resisted Date's attempt to take the knife, so Boss used sleeping gas to knock him out, and suggested Date Psync with him.

ABIS HQ, Psync Room, Monday 8:15 PM

Ota ready to be Psynced.

Date and Boss returned to ABIS to begin Psyncing with Ota.



  • The name youdAI (容態) translates to "Condition," which is in reference to Iris Sagan and Ota Matsushita's physical conditions and recuperating injuries following their attack from the New Cyclops Killer.
    • It could additionally be a reference to the conditions in which the victims' friends and family find themselves in after the attack, such as Mizuki and Hitomi's distraught reactions, as well as Mayumi's recently revealed dementia.

References to Media and Pop Culture

  • During the Free Time investigation segment at the Harbor Warehouse District, if you examine the "Crane," Date will ask "Can you please move the craaane?" to Aiba, who tells him to shut up. This is most likely a reference to the Alien toys from the Toy Story movies, who claim their master to be "the Claaaw."[1]


Kaname DateAibaIris 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


  1. Scene from Toy Story: The Claw