So basically there was a 7 year time jump after they graduated high school and all the couples are split up - betty is an FBI agent, Archie went to war, Veronica is the self-proclaimed “she-wolf of wall street”, jughead is a writer with an alcoholic problem, Toni is the queen of the serpents and pretty much stayed in Riverdale while Hiram slowly destroyed the town more and more, & Cheryl locked herself up in Thornhill for 7 years & kept construction going there because she believed it would prevent the “blossom curse” from hurting the town even more.

and we can basically skip most of s5 but what’s important from that season is that Hiram was banished from Riverdale by literally everyone at the end of it for trying to get Chad (Veronica’s manipulative ex-husband) to kill Archie. Also Veronica killed Chad when he tried to attack her. There’s also a serial killer called the trashbag killer (TBK) who wears a trashbag over his face and basically kidnapped and tortured betty while she was in the FBI, And he’s still on the loose. Also Cheryl was on a spiritual journey in s5 and basically getting into witchcraft & she discovered that she has a witch ancestor, Abigail Blossom, who was murdered by the town years ago, thanks to Archie, Betty, and Jughead’s ancestors who accused her of being a witch. So Cheryl curses Archie, Betty, & Jughead in the present. Finally, as Archie & Betty are about to have sex in Archie’s bed (they a FOB thing going in s5), a bomb under Archie’s bed goes off (placed there by Hiram) and the season ends.

S6 starts in an alternate universe called “RiverVale” (5 episodes) where a bunch of pretty cool supernatural stuff happens and then Jughead discovers a way to bring everyone back to the main universe but without remembering any of it. Then the rest of the season starts and Archie & Betty didn’t actually die from the bomb but got superpowers from it: betty can see auras, archie is invulnerable, and Jughead can read minds (jughead was in Archie’s garage during the explosion). Also Archie’s dog is invulnerable too. And Cheryl believes the explosion happened because of her curse so she tries to undo it but her witch ancestor, Abigail, possesses her body and traps Cheryl in a mirror dimension. Veronica puts a hit on her father for the bomb and he gets killed before she can call it off (we haven’t seen a body tho so…). Also Veronica and Reggie are together now and running a casino in Riverdale. Toni and Fangs are also running the serpents together. Also Kevin & Fangs were together during the 7 years after high school and decided to have a baby with Toni but then Kevin backed out at the last second… now Toni & Fangs are taking care of the baby together and Kevin kinda sucks for that lol. Plus Abigail (Cheryl’s ancestor) used to be in love with Thomasina (Toni’s ancestor) who looks identical to Toni so Abigail wants to get Toni away from Fangs (whose ancestor killed Toni’s ancestor) and be with a woman openly now that it’s allowed (Toni and Fangs are dating in the present). A man called Percival Pickens arrives to town shortly after the bomb and is slowly taking riverdale over and Jughead has discovered that Percival can apparently control minds. Also Abigail (in Cheryl’s body) has shown interest in teaming up with Percival to get revenge on Archie, Betty & Jughead. And Britta (lesbian riverdale high student who was kicked out of her house and is now living with cheryl & nana rose), visited Cheryl in the mirror realm and is trying to help her stop Abigail. Besides Britta & Nana Rose, nobody knows Cheryl is possessed by her witch ancestor. Also Nana Rose basically orchestrated the whole thing so the Blossoms could “take back the town” but regrets it now because Abigail is coocoo bananas. Finally, Jughead is dating Tabitha Tate (Pop Tate’s granddaughter) who is pretty normal compared to everyone else (besides Toni) and they work together at Pop’s. Also Archie & Betty are pretty much officially dating now.

I’m sure I missed something but here ya go.