It was Another boring day... ~Kris~ Achemmm... You were walking after School waiting for Toriel to pick you up... However you then came to Grillby's, meeting Sans again... As he spoke.

Sans: Heya kid. Uh... I need you to take care of my brother...

You said...

You: Ok

After 7 days... of taking care of Papyrus... you hear front door opening... Sans came back and now... he is now helping you...