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

Day 4: Monday -jukkAI- (4日目:月曜日 -述懐-, 4-Nichi-me: Getsuyōbi -jukkAI-, lit. Day 4: Monday -Recollection-) is a chapter featured in AI: THE SOMNIUM FILES.

It is the ninth chapter of the Annihilation Route. It covers Kaname Date's investigation of the murder of Iris Sagan and Ota Matsushita, and his interrogation of Inmate #89.

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...

When Date arrived at the scene, Iris and Ota were already dead, their bodies mutilated. With newfound determination, Date discovered that #89 was linked to the case and demanded he be brought to ABIS HQ for interrogation. #89 told the story of an assassin named Falco. Falco was an assassin that worked for the Kumakuras. One day, the former chairman Rohan ordered him to kill a mother and daughter. #89 refused to elaborate, forcing Date to Psync with him...

Story Summary

Marble, Monday 2:48 AM

Date wakes up facing Mama.

Date woke up nearly five hours after Ota knocked him out. Mama told him that Ota was gone when she returned to the bar, and she was unable to wake Date up. Soon after, 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. Aiba traced the source of the broadcast to Okiura Fishery Cold Storage Warehouse, and Date left to pursue the culprit.

Driving, Monday

Iris's livestreamed murder.

During the drive, Ota appeared on camera and turned the machine off. Date hurried, hoping to make it in time, but before he arrived, the polar bear reappeared and turned the saw back on, killing Iris.

Cold Storage Warehouse, Monday 3:35 AM

Ota's corpse inside the bear suit.

Date rushed inside to find the polar bear costume on the workbench, with someone still inside and the saw running. He turned the saw off and pulled off the head of the costume, revealing Ota, dead.

ABIS HQ, Interrogation Room, Monday 10:02 AM

Date discussing possible suspects with Boss.

Boss met Date in the interrogation room to go over the incident at the cold storage warehouse. Boss informed him that HQ had determined that Ota was the New Cyclops Killer, and committed murder-suicide, killing Iris and then himself. Date did not buy her argument, and discussed a number of inconsistencies in his possible motives and actions. He went through a list of people connected to each of the victims who would be the culprit. Mizuki had the strongest connection to all of them, but with her age, would not have been capable of killing them. Mayumi may have had motive to kill Renju and Iris, but she had no connection to Shoko, and would never kill her own son. Moma had connections to both Shoko and Renju, but none to Iris. Hitomi also had connections to Shoko and Renju, but Date could not imagine her killing her own daughter. So also had connections to the first two victims, but he had no clear connection to Iris. Date also considered himself as a suspect, but ruled himself out, since he had no memory of committing the murders. Aiba also vouched for Date, having known him well for several years now. He set out to continue investigating.

Harbor Warehouse District, Monday - Free Move

Cold Storage Warehouse, Monday

The crime scene investigated.

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. Aiba confirmed that the video was streamed live based on Iris's time of death, and that Ota had been stabbed by a kitchen knife. She also explained that Okiura Fishery was founded by Renju's father, but Renju himself never owned the company.

Outside the Warehouse, Monday

Pewter outside the cold storage warehouse.

Outside of the warehouse, Date ran into Pewter. Pewter told him that he had information about the Original Cyclops Serial Killings that he did want to give Date in front of Boss. He explained that the original Cyclops Serial Killer was actually two people. The first was an unnamed "murderous psychopath" who would commit the murders, and the second was Rohan Kumakura, who would remove the eyeball posthumously. The killer was born with a brain dysfunction that prevented him from secreting oxytocin. However, he could get something of a substitute from committing murder, which would cause his brain to release a flood of dopamine and endorphins. He had committed many murders, starting at the age of 12. Rohan, on the other hand, had developed a fascination with the eyeballs of dead women since he first took a woman's eye 18 years prior. The two collaborated on the murders—Rohan would find targets for the killer, and in exchange have an opportunity to take their eyes.

Date, realizing that one of the two killers was dead, asked Pewter what happened to the other. Pewter explained that he was currently serving a life sentence in Fuchu Prison, where he was known as Inmate #89.

Matsushita Diner, Monday - Free Move

Mayumi mourning Ota.

Date found Mayumi Matsushita at the diner. She blamed Date for being the reason Ota went to the warehouse, and asked him to leave.

Home, Monday - Free Move

Mizuki at home.

Mizuki was at home, deeply depressed after the deaths of her parents and her two closest friends. Date sat with her a while and asked Aiba to contact ABIS to find her a good counselor.

Sagan Residence, Monday - Free Move

Hitomi crying on Date's shoulder.

Date sat down to talk to Hitomi. She reminisced about raising Iris since she was a baby, and talked about how Ota had been one of her students. She also told Date that she would occasionally visit someone at Fuchu Prison, and her second meeting with Shoko occurred in the waiting room there. Before Date left, Hitomi hugged him and begged him to catch the culprit.

Marble, Monday - Free Move

A saddened Mama.

Date asked Mama for any relevant information about the case. She believed that the Kumakuras had to be connected to the case. She told Date about the Matsushita family's connection to the Kumakuras—they were widely rumored to be responsible for the chemical plant explosion that put Matsushita Diner out of business.

ABIS HQ, Monday

Boss's Office, Monday 4:57 PM

An empty office.

Boss was not in her office, so Date discussed potential leads with Aiba. They determined that their best lead was Inmate #89. Aiba explained that his real name and nationality were unknown. It was unclear whether Shoko visited Fuchu Prison to see #89, but it was a possibility. He could not have committed the recent murders, but his phone call to the police indicated he knew something, so Date and Aiba had him brought to ABIS for questioning.

Interrogation Room, Monday 8:56 PM

#89 is introduced.

#89 is brought into the interrogation room, and Date sat opposite during the process. #89 was unwilling to provide any personal information, but he admitted to being one of the two Cyclops Killers, and said that he met Shoko at Fuchu Prison. In exchange for any further information, #89 asked to be released from prison. Date agreed, and #89 began telling a story about a man he called "F."

6 Years Ago - Flashback

Harbor Warehouse District - Flashback

The location in which F took his first kill.

F was a detective who had been orphaned and raised in an abusive orphanage, and he grew up with a hatred for the evils of the world. While chasing down a criminal wanted for the assault and murder of women, the criminal taunted him about the connections he had that would let him return easily to his life of crime. F shot him on the spot, despite the fact that he was unarmed, and his higher-ups fabricated evidence to have it ruled as self-defense. From that point onward, F continued killing criminals he thought to be unjust, all while working as a detective.

Dark Room - Flashback

Rohan gives F an offer he can't refuse.

However, one of his targets (which #89 refers to as "X") was an executive of the Kumakura gang, so once F had killed him, Rohan Kumakura had F kidnapped. After torturing F, Rohan, impressed by his track record, coerced him into working for the Kumakuras as an assassin, and gave him the codename "Falco."

Golden Yokocho - Flashback

Falco assassinating a target.

Falco continued his work as a policeman while carrying out assassinations on the side. A notable assassination happened on the alleyways of Golden Yokocho.

Ikume Shrine - Flashback

Falco bleeding out.

One day, he missed his target and took a bullet to the stomach. He managed to escape and collapsed outside a nearby shrine, where a woman found him. As she began dialing for help, he heard nearby footsteps of people coming after him, so he kissed her to keep her from talking. They met a few more times, and Falco found himself falling for her and wanting to return to his former self.

Kumakura Office - Flashback

Falco and Rohan Kumakura.

He negotiated with Rohan to go clean—he agreed, but asked for him to carry out one last assassination: the woman and her daughter. Falco was cornered, so he called on an old friend for help...

ABIS HQ, Monday

Interrogation Room, Monday

#89 in the interrogation room.

#89 ended his story and refused to continue until his release procedures had cleared. Determining that he likely would not uphold his promise, Date asked Pewter to start preparations to Psync with #89.

Psync Room, Monday

Date psyncs with #89.

#89 is put to sleep and Date begins to Psync with him. Pewter starts the process while Boss is still nowhere in sight.



  • The name jukkAI (述懐) translates to "Recollection," which is in reference to #89 recounting the events of Falco's life history.


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