Archie meets KISS? What happened? Gene shows up at Archie's house, eats through his pantry and then sleeps with Betty? Geez!!
No, Sabrina the Teenage Witch cast a spell that opened up a portal to Hell and brought demons in Riverdale. At the same time, KISS was playing a concert in Riverdale, so the Archie gang and KISS teamed up to close the portal to hell and defeat the demons.
I think that's how it goes. That's what a coworker of mine told me.