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

Day 3: Sunday -syokubAI- (3日目: 日曜日 -觸媒-, 3-Nichi-me: Nichiyōbi -shokubAI-; lit. Day 3: Sunday -Catalyst-) is a chapter featured in AI: THE SOMNIUM FILES.

It is the sixth chapter featured in the Red Route of the game. It covers Kaname Date's investigation of the Renju Okiura's murder and his interrogation of Iris Sagan.

Case File Synopsis

First Shoko, now Renju. It was presumed they were killed by the same person. Their deaths matched a case from six years ago, the "Cyclops Serial Killings."

Date visited the bar "Marble" located in Golden Yokocho with Mizuki to gather intel from the owner and informant, Mama. She told them that Renju had connections to a yakuza gans, the Kumakuras. Date left Mizuki at Marble to visit the Kumakura office alone. There, he found So Sejima, the politician. The circumstances were suspicious, but there was no direct link between them. With no options left, Date headed to Lemniscate to meet Ota. After being pressured, Ota admitted that he saw Renju and Iris together the previous night. With the suspicion now on Iris, Date Psynced into her brain...

Story Summary

ABIS HQ, Boss's Office, Sunday 9:17 AM

Date meeting with Boss and Pewter.

Date discussed Renju's murder with Boss and Pewter. The two explained details of the Original Cyclops Serial Killings to Date, but insisted that the New Cyclops Killer could not be the same culprit. Boss still refused to explain why, and Aiba was unable to find any further details. Despite Boss's insistence that Date get some sleep, he headed to Sunfish Pocket to continue investigating.

Driving, Sunday

Driving from ABIS to Sunfish Pocket. Mizuki in the back seat.

Shortly after getting in the car, Date discovered Mizuki in the back seat. She told Date she had snuck out of the hospital, and insisted on investigating her father's murder with him. Mizuki also told Date about Shoko's investment fraud scheme and potential yakuza ties.

Sunfish Pocket, Sunday 10:33 AM

Date and Mizuki investigating Sunfish Pocket.

Date and Aiba gathered evidence about Renju's murder. Three 55-pound beer kegs were on the floor where Renju's body was found, and a large oil drum with Renju's watch inside was nearby. Aiba determined it was likely Renju was killed at a different location, but based on Renju's weight of 150 pounds, it may have been difficult to move the body. Aiba also informed Date that the cause of death was strangulation, and the time of death was approximately 8:00 PM on Saturday. A high concentration of sedatives were found in Renju's body, and like Shoko, his left eyeball was removed before his death. Aiba checked the building's elevator records to find that the elevator arrived on the second floor once while carrying 310 pounds.

Matsushita Diner, Sunday - Free Move

Date and Mizuki meeting with Mayumi.

Mayumi told Date that Ota left early in the morning, but she did not know where. Date asked Mayumi to contact him if he returned, and left to investigate elsewhere.

Lemniscate Office, Sunday - Free Move

Date and Mizuki speaking with the Receptionist.

Date asked the receptionist if she had seen Ota or Iris. While she did not see Ota, she let Date know that Iris was busy recording a podcast. Date asked her to contact him if she saw Ota, and left to investigate elsewhere.

Date and Mizuki in front of Marble.

Golden Yokocho, Sunday - Free Move

Date and Mizuki arrived at Golden Yokocho, and headed towards the building named Marble, where Date stated they will meet his informant.

Marble, Sunday

Upon entering Marble, Date and Mizuki heard a radio broadcast about a traffic accident that occurred the previous night. Date talked to Mizuki about her school life and the possibility of eating dinner together. Mizuki asked Date about what he did with Renju at Marble, and Aiba mentioned that Renju first asked Date to take Mizuki in four years ago.

Meeting Mama at Marble.

Eventually, Mama arrived back at the bar. Date asked her for information about Renju, and she informed Date about his ties to the Kumakura Gang. She also said that Renju's watch was an anniversary gift from Renju's new lover.

Golden Yokocho, Sunday

Stepping out to the bathroom (lies!)

Date pretended to head to the bathroom, but instead, now with the new information about Renju, he decided to investigate the Kumakuras. Not wanting to take Mizuki there, he called Boss to arrange for an officer to take Mizuki home.

Moma Kumakura.

Kumakura Office, Sunday 3:22 PM

Date got in a fight with two of the yakuza members at the Kumakura Office. After incapacitating them both, he began asking Moma Kumakura for information. Date mistakenly assumed that Rohan Kumakura was the chairman of the Kumakuras, but Aiba informed him that Rohan committed suicide one year prior, and Moma had been the chairman for six years. Moma denied any connections to Shoko.

Aiba noticed that one of the cigarettes in the ashtray was still warm, indicating that someone else had been there recently, but had no opportunity to leave. Date used Aiba's x-ray mode to find a figure hiding in a closet. As he attempted to get closer, a gunfight started with the other yakuza members. Date once more incapacitated them, and the figure in the closet was revealed to be So Sejima.

So Sejima in the Kumakura office.

Moma gave Date more information—he explained that the Kumakura gang would occasionally do work for Renju. He also mentioned that something happened to Rohan six years ago and he spent time in a special hospital. He explained that the Kumakuras were at a golf tournament during Shoko's murder and thus could not have killed her, which Aiba was able to verify. Date also questioned So, who admitted that he did business with the Kumakuras but did not offer up any details.

Date got a call from the Lemniscate receptionist that Ota had arrived, and left to go talk to him.

Driving, Sunday

Date driving from Kumakuras to Lemniscate.

Date discussed the case with Aiba, who projected herself in her human form. They discussed So, the Kumakuras, and their connection to the case, but were unable to establish a motive. Aiba explained that So used to live in the Kabasaki District, and sold all of his land there shortly before the explosion at the chemical plant.

Date received a call about a message left to the police by Inmate #89 prior to Renju's murder. #89 claimed to know who killed Shoko Nadami, and asked to be released in exchange for telling the police the killer's identity.

Ota trying to cover for Iris.

Lemniscate Office, Sunday 5:59 PM

Date met Ota in the lobby. Ota had learned that Shoko was Mizuki's mother, and felt guilty about leaving her at the crime scene. Ota denied knowing anything about Renju, prompting Aiba to show Date a thermal image of Ota's body, indicating he was lying. After Date pressured him about the sockpuppeting, Ota revealed that he saw Renju with Iris. He insisted that Iris would not commit murder, and told Date about how she inspired him to get through his writer's block. Ota continued, telling Date he saw the two enter Sunfish Pocket. When Iris arrived, Date took her to ABIS.

ABIS HQ, Sunday 8:23 PM

Interrogation Room, Sunday

Iris's interrogation.

Date interrogated Iris about her involvement with Renju's murder. He confirmed that she would be familiar with Sunfish Pocket thanks to the year she spent working there, and asked why she neglected to report the crime earlier. Iris said she had to record her podcast and would have been late if she went to the police. Iris claimed she was at home during the time Renju was murdered, and said that Hitomi was out of the house and could not confirm her alibi. She gave a timeline of events, and her use of exact times led Aiba to be suspicious of her story.

Iris pressured further.

Iris argued that it would have been difficult for someone of her stature to strangle Renju. Date said that Renju had been sedated, and it would have been possible. Iris then argued that she would not have been able to hang the body, but Date explained how she could have used the filled beer kegs as weights. He also explained how she could have transported the body by rolling it in the oil drum. Date also observed that Renju, Iris, and the oil drum's combined weight matched the elevator records.

Date taking Iris's phone.

Aiba noticed that Iris was acting strangely. Using the mirror and the security cameras, Date caught her using her phone under the table. When he and Boss examined the phone, they saw Ota's message: "I won't tell anyone about that thing!" Iris refused to elaborate on "that thing," and Boss encouraged Date to Psync with her to learn more.

Psync Room, Sunday

Iris in the Psync Machine.

Iris is given anesthetic to fall asleep and placed on the Psync Machine. Date sits on the opposite side and prepares to Psync with Iris.



  • The name syokubAI (觸媒) translates to "Catalyst." It could be in reference to Iris Sagan being the suspected "catalyst" of Renju's murder plot.

References to Media and Pop Culture

  • During the Free Time investigation segment at Marble:
    • If you examine the "Bottles on Counter," Date will think to himself "9! 9 bottles! There are 9 bottles on the counter." This is potentially either a reference to the game Zero Escape: Nine Hours Nine Persons Nine Doors –which had a heavy use of the number 9–, or a reference to the folk song "99 Bottles of Beer," which contains the line "99 bottles of beer on the wall, 99 bottles of beer."[1]
    • If you examine the "Poster":
      • Before Mama returns, it will read "The Talented Mr. Dickley." The poster is a sex parody of the psychological thriller novel and movie The Talented Mr. Ripley.
      • After Mama returns, it will read "One Flew Over The Cock's Nest." The poster is a sex parody of One Flew Over The Cuckoo's Nest, a novel-turned-play-turned movie.
  • During the 5:59 PM investigation segment at the Lemniscate Entertainment Offices, if you ask the Receptionist "Do you want to get some food sometime?," she will respond by saying that she's a Reptilian (mistaking the word for "vegetarian"), to which Aiba states is a "reptilian, humanoid alien" capable of shape-shifting into human form. This is a reference to a conspiracy theory regarding an alien race of shape-shifting reptilian humanoids, that have taken root in human society and achieved political power.[2]


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. Wikipedia page for 99 Bottles of Beer
  2. Wikipedia page for Reptilian conspiracy theory