Season synopsis
Contains spoilers for this season and earlier seasons.
Jason Blossom's death starts the school year under a cloud of suspicion: his twin Cheryl says he drowned, but the discovery of his body and a gunshot wound makes Archie, Betty, Veronica and Jughead question the story. Their search moves through the Blossoms' guarded household, the Southside and Riverdale's own families. Betty's missing sister Polly returns pregnant by Jason, while Jughead's father F.P. is arrested after police find evidence linking him to the murder.
The investigation keeps shifting as F.P. confesses to taking Jason hostage and shooting him, yet Betty and Archie suspect he is protecting someone. They learn that Jason had planned to leave town with Polly, and that the Coopers and Blossoms share a family history that makes the young couple cousins. A recording from Jason's jacket finally shows what happened: his father, Clifford, killed him after Jason discovered Clifford's drug business and threatened to expose it. Clifford's death closes the case, but leaves Cheryl facing the wreckage of her family and the town's secrets.
The murder is solved before the finale, which turns to its aftermath. F.P. remains in custody, Jughead moves to Southside High and accepts the Serpents' offer of protection, while Betty and Jughead say they love each other across the growing divide between their lives. Cheryl survives a plunge into the icy Sweetwater River and burns down Thornhill. As Archie and Veronica begin a relationship, a masked robber shoots Fred Andrews at Pop's, ending the season with Archie holding his wounded father.