After Sonic, Frisk, Chara, and Toriel went to the other room, Toriel ran ahead and stood next to the door leading to the next room. Sonic and company looked around. It looked like a giant hall, with purple walls, white stairs, red leaves... and...

"What's that?" Frisk wondered. This kid read my mind! Sonic thought, amazed.

"That is a SAVE point, my child. You can heal and save your progress there. It also can fill your determination." Toriel replied. Sonic decided not to ask what the heck this "determination" was. Obviously the Underground ran on its own rules. He had been filled with determination before, but the way Toriel had phrased it, it almost seemed like a substance. Frisk moved to the SAVE point. Instantly, they looked a lot healthier and brighter. Sonic was stunned, but he quickly recovered.

"Are you feeling better?" Sonic asked Frisk.

"Much better," Frisk replied.

"Come, my children! We must press on!"

They went into the next room.

Then they had to go throughout multiple puzzles with Toriel guiding them.

Soon, they met the first monster other than Toriel: a Froggit. Sonic didn't feel an urge to hurt it, which was helped by Toriel saying to spare it. Frisk spared it, and then Toriel came in to help, making the Froggit go away.

They moved through a lot more rooms. Sonic and Frisk were getting along. The spike room Sonic wall-jumped.

"Well, that was easy," Sonic said. "Where to next, Toriel?"

"Now, I have to test your independence. Please forgive me." Toriel ran across the room and hid behind a pillar. Sonic blitzed across the room. Frisk and Chara followed at a much slower pace.

"Hey, Toriel... in my world, I've been through a lot. Destroying a crazy doctor's schemes, turning into a Werehog, helping free aliens, saving my world and countless others more times than I can count- Oh yeah, and I got sucked into STORYBOOKS, KING ARTHUR AND THE ARABIAN NIGHTS, FOR CRYING OUT LOUD, I met my past self a lot of times, I DIED AND GOT KISSED BY A HUMAN PRINCESS, FOR CRYING OUT LOUD, and I did a lot of other things on my own, with a few friends I made along the way. One of my friends is a two-tailed fox who is a genius, and an expert pilot, one of them is an echidna whose sole duty is being the guardian of the Master Emerald-" Sonic paused, took out the briefcase in his quills, opened it, and took out the large green gem- "-here, and a lot more friends I made. I'd say I'm the most independent one here. But I have friends that have my back." Sonic put the Master Emerald back and stashed the briefcase in his quills.

"Oh my..." Toriel said, in shock. Frisk and Chara also stared in shock. Who exactly was this hedgehog?

"Wow..." Frisk finally said. "I have a lot of questions."

"I'll answer them later, okay?" Sonic replied. "Anyway... Toriel, where to next?"

"Well, seeing as how you have both proven your independence... I will give you both cell phones. If you need anything, just call! Not... not that you're going to leave... it's just... in case..."

Sonic shrugged at that last part, but he wondered, Why doesn't Toriel want us to leave? Ah well. I guess I'll find out later.

So Toriel left them and went to her house.

...

As Frisk and Sonic solved puzzles and spared monsters, Sonic decided to strike up a conversation with Chara.

"So, Chara, what's your story?" Sonic asked.

"Well, it's not a very happy one..."

"It can't be worse than mine... can it?"

"Well, let me just sum it up for you. A long time ago, the king and queen had two kids. One human, one monster. I was the first human to fall. I was that human. The monster... Asriel... was my best friend..."

"What happened? Did he... die?" Sonic asked, in shock.

"No. We both did..."

"Oh...man..."

"It was mutual. It was a plan that went wrong."

"Oh man..."

"I died first. I convinced Asriel to absorb my soul."

"What do you mean?"

"I wanted to free monsterkind from this prison... but... it didn't go very well."

"I convinced Asriel that we would get 6 human souls and be free from this horrible prison. I ate a ton, literally, of buttercups- those sickly yellow flowers that you saw... It was a horrible, horrible way to die, but the way I saw it... it would all be worth it. Asriel was wracked with grief, and so were the king and queen... but Asriel absorbed my SOUL and went to the surface. I requested that my body be laid on the flowers in the village that I loved. The king and queen knew that they couldn't do that, but Asriel and I could. However... as we were laying my body down on the flowers- Asriel and I were controlling the same body, by the way- it all went wrong. I hated humanity, you see, and I still hate them, but I don't want to talk about what they did to me before I fell... so let's talk about what they did to Asriel and me. Anyway, a human saw us, and they thought Asriel killed me. So, the human attacked us. I wanted to retaliate... but Asriel refused. We suffered blow after blow, until we got back to the Underground. Then, the king and queen realized what happened, but it was too late. We turned to dust, crying for help... but nobody came."

Sonic and Frisk, who decided to stop what they were doing, stared in shock.

"And the worst part? I should have known that it was a STUPID PLAN FROM THE START! Now I have no idea what happened after we died! And I got awakened by Frisk, and I have no idea HOW MUCH TIME HAS PASSED SINCE I DIED! And the even worse part?! ASRIEL'S DEAD BECAUSE OF ME! I KILLED HIM! AND I NEVER EVEN GOT THE CHANCE TO SAY I LOVED HIM AS MY BROTHER! MY BEST FRIEND IS DEAD, AND I KILLED HIM!"

Chara, wracked with grief, sobbed uncontrollably. Frisk and Sonic were still in a shocked stupor. Eventually, Sonic and Frisk comforted Chara. "Hey, at least you realize your mistakes, and I think Asriel would have wanted you to carry on. Also, not all humans are bad. One of my friends had a best human friend that would never have harmed anybody. Maria and Shadow were the best of friends... until a G. U. N. soldier killed Maria. Shadow has to live with Maria's death, but he's still here. And sure, some humans are bad, but not all of them are. Some humans are good to their cores." Sonic smiled his iconic smile, and said, "So don't worry! Frisk here won't hurt you! And neither will I! Right, Frisk?" Frisk nodded in agreement. "So, how about we get out of here, and go to Toriel's house?" Chara sniffed, smiled through their tears, and said, "Sure, let's go."

So they solved all the puzzles, spared all the monsters, and soon they were at Toriel's house.

"Oh, my, that took longer than I expected. I suppose I should- Oh, you're already here! Come, my children. Welcome home!"

After that, Frisk went to the SAVE point, and the four of them went inside.

Hi! Archaeopteryx108 here. I hope you're enjoying my fanfiction so far! I have had this idea for a while now. So, this is the first draft of my fanfiction. I'll edit it when it's finished. Also, the armored briefcase is black, by the way. You may have noticed that I skipped Napstablook, if you've played Undertale. The reason I skipped him was that he wasn't that important to the story I wanted to tell. Again, this is the first draft, and also, I'm writing this at 1 in the morning. Anyway, stay tuned, and stay determined!