Chapter Summaries

Lust told Killer, Murder, and the others how a human’s soul trait led Dr. Gaster to infect every adult monster in his world with lust, making life in the Underground brutal. He revealed that Papyrus secretly supported MTT, and the visitors were left confronting the discovery that Gaster existed in Lust’s timeline.

• Lust invited the Sanses into his home and asked why they had come.
• Killer explained that they traveled between worlds to save those who were suffering, and Lust began describing his world’s history.
• Lust said the queen had miscarried, then a human fell into the Underground and was killed by the king; Dr. Gaster extracted a lust trait from its soul.
• Killer and the others reacted with shock when Lust mentioned Gaster, and Lust realized he might not exist in their timelines.
• Lust explained that Dr. Gaster injected every adult monster with the trait, worsening the Underground’s problems and turning the Royal Guard brutal.
• Lust said MTT had not been injected and that Papyrus secretly supported her, hoping she could find salvation.

Lust explained that the soul trait injected into the Underground had corrupted its inhabitants, and that his attempts to remove it had failed. Murder showed him a photograph of a Determination Extractor, suggesting it might help.

• Lust told Murder and Insanity that he had sought Alphys and Dr. Gaster's help, but they had already been consumed by the lust trait.
• Lust described giving up after seeing the Underground's brightest minds focus on satisfying their lust.
• Murder asked whether Lust had tried using a machine to extract the trait, and Lust showed them a device that suppressed his lust but could not eliminate it.
• Murder showed Lust a photograph of the Determination Extractor, while Killer questioned why he had taken a picture of it.

Murder, Killer, and Insanity discovered that Lust’s world had a hidden True Lab beneath Alphys’s unusually suggestive laboratory. MTT spotted the four Sanses on surveillance and went to conceal the entrance again.

• Lust said he had never heard of the True Lab, surprising Murder, Killer, and Insanity.
• Lust brought the group to Alphys’s pink laboratory and explained that its inhabitants used NSFW items to release pent-up desires.
• Murder uncovered the hidden entrance and revealed a dilapidated elevator leading to the True Lab.
• MTT saw the four Sanses on the surveillance feed and realized they knew about the concealed entrance.
• MTT turned off the feed and went to hide the door again before returning to his show.

Murder, Killer, and Insanity planned to use the Determination Extractor to remove the lust contaminating the monsters’ souls, despite the machine’s dangerous limitations. Murder left with Lust to find the first human’s soul and obtain a sample of the lust trait while Killer and Insanity prepared the machine.

• The four of them arrived at the abandoned Determination Extractor, and Killer explained that it could extract traits from souls.
• Murder, Killer, and Insanity told Lust they intended to remove the lust from every monster’s soul, but warned that the machine could only process one being at a time and might take the target’s soul too.
• Murder proposed using extraction molecules and the lust factor to create a targeted nano-enchantment mesh for the Core’s ozonated water generator.
• Murder asked Lust where the first human’s soul was kept, and Lust took him to find it while Killer and Insanity stayed to prepare the machine.

Lust led Murder into Gaster’s hidden maze to retrieve a soul, warning him about lust-driven monsters that could not be destroyed. When one of the creatures drew near, Lust hid with Murder and asked him to help boost a device that concealed their lust.

• Lust explained that Gaster had stored souls in the maze and that only monsters related to Gaster could take the restricted soul.
• Lust told Murder that he was Gaster’s son and warned him that shortcuts would not work in the maze.
• Lust described how revived monsters hunted living creatures by sensing lust, then led Murder deeper along the route to the soul.
• After hearing a monster’s heavy breathing, Lust pulled Murder into a hiding place and asked him telepathically to boost his lust-concealing device.

Murder and Lust sneaked through a maze of desire-mutated monsters to extract a sample from the human soul. After they sealed the soul’s container, an enormous Amalgamate burst into the room, leaving them facing a likely fight for survival.

• Murder used the device to hide himself and Lust from a monster, and Lust revealed the creature’s grotesque form with a flashlight.
• Lust explained that the monsters became more mutated deeper in the maze and guessed that the human soul’s desire trait had restored itself.
• Murder handed Lust a syringe, and Lust opened the soul’s barrier and extracted a small sample.
• A gigantic Amalgamate smashed into the room, and Murder prepared to fight while Lust said they were probably going to die.

Murder and Lust faced a monster that lusted after the sealed human soul, and Murder used Gravity Manipulation to pull Lust out of danger. He prepared his simulated Anti-Determination attack against the monster, though he explained that the technique could not defeat humans because their determination quickly reunited.

• Murder sealed the soul container before he and Lust dodged the monster's charge.
• The monster stroked the soul container and declared Murder and Lust adorable, prompting Murder to attack it with bones.
• Murder spotted the monster's pink energy through the smoke and pulled Lust away before it could reach him.
• Murder summoned a Shock Waves cannon and charged it with simulated Anti-Determination.
• Murder explained that Anti-Determination could sever an Amalgamate's determination, but would fail against a human and drain his stamina and magic.

Murder used an energy that could dissociate lust to destroy an otherwise regenerating monster. After Murder and Lust escaped detection, Murder proposed that they do more to save Lust’s world before leaving.

• Murder fired a blood-red blast that tore away half the monster’s body and stopped it from regenerating.
• Murder explained that his power could dissociate determination and lust, though using it took a lot out of him.
• Murder turned a barrage of bones red and blasted the monster into ash after it begged to be kept alive.
• Murder took the device from Lust and switched it back on at 200% power, hiding them from the monsters still wandering the maze.
• Murder told Lust that leaving right away would be too hasty since they had come to save his world.

Murder and Lust cleared the remaining monsters from the True Lab, and the group began using Lust’s soul trait in the Determination Extractor. The extractor’s sphere started turning purple as Murder prepared to generate the Enchantment Web.

• Murder warned Lust that the monsters could keep mutating, then took over clearing them out after confirming Anti-Determination stopped their healing.
• Killer and Insanity waited at the True Lab and discussed how long retrieval missions in comics and novels often led to fights.
• Murder and Lust returned, with Murder exhausted after fighting several fast monsters at close range while Lust drew some of their attacks.
• Killer told Murder that the extraction simulation was ready, and Murder confirmed they had obtained Lust’s soul trait.
• Insanity injected the soul trait into the Determination Extractor, causing its blue sphere to begin shifting toward purple.
• Murder said the next step was to generate the Enchantment Web.

Murder used his magic to create an Enchantment Web with the Determination Extractor. He took the finished mesh and prepared to go with Lust to the Core to purify the Underground.

• The group used the Determination Extractor to synthesize a material that could selectively absorb desire.
• Murder revealed that he could use his magic to make the Enchantment Web directly.
• A dark mesh with a purple glow formed inside the extractor, and Murder took it in his hands.
• Murder invited Lust to go with him to the Core and purify the Underground.

Lust and the others restored normal desire to the Hotland universe by placing an Enchantment Web over its water outlet, then traveled to another spacetime. They landed on a grassy track resembling a Sonic game, where Killer demonstrated how Gold Rings worked.

• Lust and Murder confirmed that the Enchantment Web was channeling magic into the purified water and would gradually remove the excessive desire from people's souls.
• Lust thanked the group, and Killer opened a rift so the four could leave the Timeline.
• The group discussed their first mission and hoped their next journey would not involve another Amalgamate.
• Killer misaligned the rift again, and the group landed together on a grassy track dotted with Gold Rings and enormous loops.
• Killer explained that she had played a game featuring a hedgehog and said Gold Rings could absorb damage before being knocked out of the player's body.
• Killer used Gravity Manipulation to touch the overhead Gold Rings, which were drawn into her body.

Murder, Killer, and Insanity discovered that the timeline they entered had already suffered a genocide, then watched its world turn bloody and chaotic. When a sinister Sonic appeared and opened his eyes, darkness swallowed everything, leaving Killer alone and unable to find the others.

• Killer checked the timeline and told Murder and Insanity that its genocide had already been completed.
• The sky turned blood red, the rivers became blood, and the trio found the bodies of small animals gruesomely killed.
• Killer recognized the blue hedgehog as Sonic, the character she had controlled in a game, and said he had never killed anyone there.
• As the trio approached Sonic, the timeline descended into chaos and garbled white characters filled the air.
• Sonic opened his dark, blood-filled eyes and laughed, plunging the surroundings into darkness.
• Killer lost sight of Murder and Insanity, called for them, and probed the darkness with a dagger.

Killer was forced to run across a burning Angel Island while a terrifying figure chased her, then entered a stone maze after descending into a pit. At the maze entrance, a voice invited her to play hide-and-seek, and Killer was left with no way back.

• Killer was teleported to a burning Angel Island after a blood-written message invited her to play a game.
• Phantom images of Sonic startled Killer and made her run faster along the island’s only path.
• Killer heard something chasing her and narrowly dodged a blue figure she recognized as Sonic.
• Killer used Gravity Manipulation to descend into a bottomless pit and landed in a stone maze.
• A voice asked Killer Sans to play hide-and-seek, leaving Killer trapped at the maze entrance.

Killer explored a stone maze while Horror Sonic hunted her, then used a color-changing Big Ring to escape. She jumped into the ring after Sonic.EXE entered it and it turned blue.

• Killer searched the maze and hid from Horror Sonic when she heard his footsteps.
• Killer tried the springs, but a red spring brought Horror Sonic close enough to jumpscare her.
• Killer fled from Sonic.EXE until she reached a dead end and a gray Big Ring.
• Killer teleported behind the ring, and Sonic.EXE charged into it, turning it blue.
• Killer jumped into the blue Big Ring.

Killer traveled through a dead forest beneath a blood-red moon while searching for Murder, and encountered a figure who looked exactly like him. She followed the figure as he claimed to be Murder and led her toward a fork in the path.

• Killer entered a lifeless forest and continued onward, determined to find Murder and escape with him and Insanity.
• Killer saw a charred corpse hanging overhead, then encountered a hooded figure with Murder's face.
• The figure claimed he had always been Murder and said he had appeared in the forest after seeing Sonic, with Insanity missing.
• Killer and the supposed Murder walked together until they reached two paths, and he confidently chose the one on the left.

Killer escaped a disguised monster through a Gold Ring, while Sonic.EXE set the forest ablaze and disappeared. Insanity arrived in a chemical factory, where a fast blue hedgehog pursued her and a red Gold Ring appeared before an impassable wall.

• Killer trapped Murder beneath Blue Bones, fled in the opposite direction, and escaped through a Gold Ring.
• Sonic.EXE arrived after Killer had escaped, set the forest on fire, and vanished.
• Insanity fell into a chemical factory filled with red fog and blood-stained floors after a visual glitch.
• A fast creature pursued Insanity, and she continued forward after her attempt to punch it failed.
• Insanity reached a towering wall that she could not bypass with shortcuts, then noticed a red Gold Ring falling from the sky.

Insanity used Red Rings to pass through enormous walls into a world that rejected normal people, but the second ring left her trapped in madness while a terrifying blue hedgehog pursued her. Apparitions of the people she had killed then surrounded her, leaving her frightened and alone.

• Insanity touched a Red Ring, entered a heightened state of madness, and passed through the first enormous wall before it reappeared behind her.
• After her madness subsided, Insanity saw a blue figure vanish and continued through the strange world.
• Insanity picked up another Red Ring and used Shortcut to dodge a blue hedgehog's attack, but her Shock Waves did no damage.
• Insanity escaped past the second wall, but her madness persisted as apparitions of Toriel, Papyrus, Asgore, Alphys, Undyne, and the others accused her of killing them.
• Insanity panicked as the apparitions surrounded her, realizing there was no one normal beside her.

Insanity escaped the phantoms in the Chemical Factory after her madness state ended, then entered a temple and found a seemingly endless, trap-free passage. The chapter left her facing a shadowy figure with familiar red eyes.

• Insanity realized the phantoms were illusions and smashed through them, but more kept appearing.
• A shadowy Papyrus attacked Insanity, and her madness state ended just as he lunged at her.
• Insanity climbed over a low wall and entered a temple that sealed its entrance behind her.
• Insanity took a blue-flamed torch and walked down the temple passage for ten minutes without encountering traps.
• Insanity's combat form activated as she spotted familiar red eyes in the shadows ahead.

Insanity escaped Sonic.EXE’s looping Temple by using a golden ring, while Murder searched a dark, checkered place and realized something was watching him. The chapter left Murder alone and unable to see his hidden enemy.

• Insanity realized Sonic.EXE was making her run in circles and tried changing the direction of her shortcut.
• Insanity escaped the Temple, found a glowing golden ring, and vanished after touching it.
• Sonic.EXE laughed at Insanity’s escape and turned his attention to her last friend.
• Murder explored a dark, checkered area using a small magical flame for light.
• Murder spotted red eyes watching him from a wall, but they vanished before he could see what was there.

Murder fell through a smoke-filled pit into a laboratory, where Metal told him about Sonic.EXE and Dr. Eggman’s plan. Metal led Murder toward a Big Ring, where his friends might appear if they survived.

• Murder jumped into a deep pit, cleared away the smoke with Giant Shock Waves, and slowed his fall with Gravity Manipulation.
• Murder landed in a laboratory and met Metal, who said Dr. Eggman had sent him to guide Murder.
• Metal explained that Sonic.EXE was an impostor possessed by a demon that had fused two timelines.
• Metal told Murder that his friends might enter a Big Ring if they survived, then led him toward it.