* To know more, see:
During a Genocide run, Frisk tries to reset but in the process, a glitch appears that keeps getting bigger and bigger.
The monsters are on the surface, but it is not the utopia they think it is. The Anti-Monsters Department will fight hard to get rid of the monsters, and that is not even the biggest threat the monsters face...
Also, there are spoilers in the first two in season two, you have been warned.
Frisk does genocide and makes it to Sans. Frisk decides to reset while fighting Sans, but Chara traps them before they can. Frisk is then locked out of undoing their mistake, or of continuing. Chara has taken total control. Frisk manages to break free and takes the killing blow for Sans, giving him their soul and their determination. Sans defeats Chara and resets the timeline.
Having witnessed Chara battle Sans, Gaster tries to bring himself back into existence by stealing Frisk's soul. Gaster summons Frisk to The Void to kill them, but Sans comes to the rescue. Frisk gave Sans their soul again and Gaster is defeated. Sans resets once more.
Because of Sans's repeated absorbing of Frisk's soul and then resetting, the timeline is glitched enough for Chara to return. Chara sets their sights on stealing as much determination as possible. Flowey warns Sans that Frisk is in danger and they team up to stop Chara. Chara takes Frisk's determination, and Sans and Flowey escape with an un-determined Frisk.
It's time for round two against Chara, and this time, Sans brings back Gaster to help him and Flowey with the fight. Flowey absorbs the six human souls and becomes Photoshop Flowey, and they go to fight Chara. Frisk gets their determination back when they see that their friends are losing, and calls for help from the souls who get their traits back as well, which they had lost in the fight against Chara. Frisk gives their soul to Flowey, who then changes into Asriel.
Asriel vs Chara. Two friends opposing each other with the entire timeline in the balance. Chara explains to Asriel why they are doing this, and asks him to help erase the timeline. Asriel refuses and they fight, but in the end he cannot go through with it. He finds a way to spare Chara, but Chara could not exist without their determination, so they gave Asriel the remains of their soul. Asriel destroys the barrier and monsters go to the surface. Frisk shatters the reset button and promises Sans to only continue from now on, so they can all look to the future.
Frisk finds that being the ambassador isn't as easy as it seems. They have to convince Jessica Grey of the Anti-Monsters Department, or AMD, to show up and sign at a conference. Along the way, Frisk sees a lonely child walking across the street moments before a speeding car nearly hits her. They jump in saving the child and destroying the car. The young girl introduces herself as Betty, becoming an immediate fan of Frisk for all they are doing for the monsters.
Betty decides to tag along and try to help Frisk convince Jessica to sign the peace treaty. Frisk figures they should show the pontential monsters have to helping humans by bringing Jessica to Gaster's lab to show possible advancements that could be made, and Toriel's school for the kids with soul traits.
Sans and Asriel also speak, and after Asriel apologizes and requests that Sans not look at him the same way he looked at Flowey. Sans then accepts Asriel's friendship.
While at the school, Jessica has a flashback and leaves, crying. Toriel talks to Betty, which causes a pink blob to appear to defend Betty. Betty tells them that it's called Akumu, or Kumu for short. Betty and Frisk then go to look for Jessica.
Sans and Asriel see Frisk and Betty while they're looking for Jessica. Betty revealed that she had a unique soul color: a pink soul. The group decides to visit Gaster's lab hoping to find answers to Betty's soul.
The next day Frisk goes to the conference and talks to Jessica. Jessica confessed to Frisk that she'd once had a daughter, who'd run away, and she agreed to sign the paper to give monsters equal rights.
Asgore was asked to explain how the barrier had been broken, and he admitted that he had killed six children for their souls. The last child, with the soul of 'integrity', was Jessica's child who had run away. Jessica yells at Asgore and leaves the meeting, swearing vengance. A mysterious figure offers to Jessica its help destroying the monster race. Jessica agrees to meet it and make a plan to destroy all the monsters.
Asgore is in jail, for killing the six human children who fell into the underground.
Frisk stops by Gaster's lab and sees that Betty is still at the lab, because her family is moving and she needed a place to stay while her things were moved.
Frisk takes Betty to go to Mettaton's interview with Sans, Papyrus, and Asriel. When they get there, Papyrus hears a cry for help. He looks around and sees a girl clinging onto the top of a construction crane. Papyrus goes to assist and the girl directs Papyrus to move the crane over the building and to push a button, which drops the I-beams that had been in the crane's grasp drops on the building, and she vanishes. Sans attempts to stop the falling I-beams while everyone gets out of the way, but Jessica Gray shoots a weapon that uses soul energy at him from the shadows, that neutralizes Sans' powers and resulting in the deaths of several innocent people. Papyrus is arrested for causing their deaths and the destruction of the building.
Sans, Frisk, Asriel, and Betty have a meeting to decide what to do. Asriel thinks that they should check the Anti-Monster-Department (AMD) cameras to see if they missed anything, which Sans agrees to.
Frisk reluctantly suggests that they try to find a way to reset and stop this from even happening. Sans gets very angry, almost attacking Frisk. He takes the friendship bracelet Frisk had given to him off his wrist and throws it on the ground, saying that Frisk should have just let Chara kill him.
Sans goes with Asriel to infiltrate the AMD headquarters, leaving Frisk behind. In the AMD room, Asriel and Sans uncover evidence about Betty could create holograms and had been manipulating everyone.
Meanwhile, Gaster decides to read the story of the twin siblings, two wizards who had created the barrier, and discovers what trait the pink soul represents: fear. Betty was a Bete Noire - a creature who's sole purpose was to make sure humans and monsters could never live in peace.
Back at AMD headquarters, Betty appears right after Sans and Asriel figure out she was behind what happened with Papyrus and the crane. Jessica shoots Sans with the special weapon again, and this time it cracks her soul. Sans is left unable to teleport him and Asriel away.
Betty made Asriel believe she is Chara with her hallucinations, and is about to take Asriel's soul when Sans finds the determination to teleport in front of him, taking the blow for Asriel.
Betty takes Sans' soul and feeds it to Akumu, her pet, killing Sans instantly. Gaster feels Sans death as he loses the glow in his right eye. Angered at the death of his friend, Asriel attcks Betty, but she uses Akumu to block his attacks. Asriel is about to attack again when Sans' words echo through his mind, telling him to warn the others. Asriel flees the battle.
Betty demands Jessica's vial of hate. Betty uses Akumu to pin Jessica to the wall and causes Jessica to hallucinate, seeing her daughter in Betty's place, pleading for the vial. The image of Jessica's daughter changes to be bleeding and terrifying. The episode ends with Jessica screaming in horror, and Betty telling her that she'll keep her promise: turning monsters into dust.
Frisk is practicing their apology to Sans for mentioning their idea to reset, which made Sans upset with Frisk. Frisk doesn't think the apology is good enough. Asriel returns without Sans. Frisk then asks Asriel where Sans is. Asriel begins to tear up, and Frisk falls to the ground, loosing some of their determination with the realization that Sans has died. Asriel tells Frisk that they need to let everyone know before Betty hurts anyone else.
Meanwhile, Akumu tries to entertain Betty, and Betty tells Akumu to try not waste its energy keeping her entertained, because they need to save it for the soul harvest. Akumu then opens its mouth, revealing that Sans' soul had enough energy to start their plan.
Jessica visits Asgore, and she also mentioning that she needs to talk to Papyrus afterwards. Asgore apologizes to her, and Jessica replies by saying that she should be the one apologizing. Because of her, Papyrus was framed and that a monster had been killed. Undyne asks if it was a short skeleton and Jessica confirms that it is. Undyne then takes Jessica to apologize to Papyrus for being a part of his brother's murder.
Jessica started crying and apologizing. Papyrus immediately forgives her, giving her a hug. Jessica's soul trait, integrity, returns.
Asriel and Frisk go to Gaster's, witch is very messy. Alphys is trying to clean up the mess. Alphys explains to Frisk and Ariel that Gaster isn't coping that well with Sans' death. Frisk goes outside to the backyard to see Gaster, who is talking to himself, sounding very hopeless.
Gaster reveals to Frisk that only Determination can defeat Fear, and vice versa. But he also tells Frisk that fear has a limit, and determination doesn't, causing them to become fully determined again.
Pink blobs being controlled by Akumu appear, attacking Alphys, who gets protected by Asriel. Gaster and Frisk are attacked as well.
After the battle, Gaster says that he and Alphys had a plan to destory Betty and Akumu, and that Frisk and Asriel should go to the school to protect the children from the blobs.
Undyne, Papyrus, Asgore, and Jessica come to Gaster's home. Gaster immediately attacked Jessica, and Papyrus protected her. Jessica tells Gaster that she can help him defeat Betty.
Gaster teleports Frisk, Asriel, and Asgore to the school. Inside, a girl, Abigail, is attacked by a pink blob, but is rescued by a boy, Cam, and a girl, Robin. Toriel then arrives and tells the children to hide.
Alphys, Jessica, and Gaster travel to a lab, where Gaster will attempt to kill Betty, but if it fails, Alphys is to activate the Nullifier, the room they battle in, and destroy Betty, and possibly Gaster. Betty arrives, and she and Gaster fight.
At the school, Cam, Abigail, and Robin are looking for Cam's little sister, Lily, who was last seen in the cafeteria. Frisk saves them from a blob, and agrees to help look for Lilly. Lily then runs by, being chased by another blob. Frisk deals with another blob while Cam, Robin, and Abigail follow Lilly.
Gaster is winning against Betty. He's almost defeated her, and Betty says to Akumu that she only needs one more soul.
Cam finds Lilly and is leading her to safety when Lilly is attacked by a pink blob, but Cam sacrifices himself and gets his soul taken instead.
Betty uses a move called 'Rhabdophobia' to take control of Gaster's powers and use them against him. She destroys him, and is about to take his soul.
Jessica blasts Betty with a gun that feeds off of her soul's energy. Alphys then tells Jessica to escape with Gaster while she activates the Nullifier. Jessica and Gaster get away using a teleporter, while Alphys stays and shields herself from the Nullifier, activating it. At Gaster's lab, Undyne realizes that Alphys isn't with the group, and rushes back to save her. In the Nullifier, the plan appears to have worked, but Betty reveals that she isn't a monster or a human, so the Nullifier proved ineffective. She then steals Alphys' soul, right about when Undyne arrives. She then tricks Undyne into destroying Alphys' soul.
Betty kills Undyne too, and starts to leave, but Undyne transforms into her Undyne the Undying form, ready to avenge Alphys.
Undyne the Undying and Betty fight. Undyne starts winning because of her determination and almost kills Betty.
MORE COMING SOON
The rest of the story cannot be told yet.
- In Do or Die, when Akumu opened their mouth and have Sans' soul in it, there are theories that Sans isn't dead yet, just trapped inside the Soul and Akumu.
- However, it has been confirmed that Sans will never return.
- Gaster has his power linked to Papyrus and Sans's. If one were to die as Sans did, he would in turn receive a power boost, regaining the magic he used to first create them.
- The monsters have started to gain physical forms from eating human food.
- This allows them to both bleed and hold determination.
- Season 1