Riverdale 3×21 “The Dark Secret of Harvest House” Season 3 Episode 21 Sneak Peek – CHALLENGE ACCEPTED — Veronica (Camila Mendes) turns to Mary (guest star Molly Ringwald) and Archie (KJ Apa) for help after uncovering a secret that Hiram (Mark Consuelos) had been keeping from her. Betty (Lili Reinhart) raises questions after witnessing some strange activities at The Farm. Jughead (Cole Sprouse) finds himself one step closer to uncovering the Gargoyle King’s identity. Madelaine Petsch, Marisol Nichols, Skeet Ulrich, Casey Cott, Charles Melton and Vanessa Morgan also star. Rob Seidenglanz directed the episode written by Cristine Chambers & James DeWille (#321). Original airdate 5/8/2019.