With palladium acting as his personal kryptonite, Archie decides he must build up his tolerance if he's going to stand a chance against Percival. Betty turns to Jughead for help uncovering some repressed memories from her childhood. Meanwhile, Veronica deals with a bombshell discovery that effects how she interacts with people around her, and Cheryl debates whether she should reach out to a former childhood crush.

After failing to get Pop's declared a historical landmark, Tabitha enlists Archie's help saving the diner from Percival. Betty opens up to Agent Drake about her ability to see people's evil auras. Meanwhile, after Reggie and the shareholders declare war on Veronica, she turns to Jughead for help maintaining control of the Babylonium. Finally, Cheryl reconnects with her childhood crush Heather, and Toni and Fangs continue their fight for custody of Baby Anthony.

After learning that Percival is exploiting his new work crew, Archie and Tabitha devise a plan to help protect the workers and get them out from under Percival's control. Meanwhile, Jughead finds himself with a target on his back after Percival catches wind of a scheme he and Veronica hatched against Reggie. Finally, Betty receives some unexpected news about a dark moment from her past, and Toni and Fangs find themselves at a crossroads.

In order to catch the Trash Bag Killer once and for all, Betty devises a plan to hold a serial killer convention in Riverdale. Elsewhere, Cheryl receives some news about Toni and Fangs that sends her spiraling, while Archie and Tabitha try to loosen the grip Percival has over his workers.

As the gang plan an event celebrating two of their own, strange biblical plaques around town threaten to put a damper on the special day.

When several of their own fall prey to Percival's latest plan, Cheryl calls upon fellow witch Sabrina Spellman for help. Elsewhere, Percival gives Reggie an ultimatum.

When Archie and Veronica's attempt to negotiate with Percival doesn't go as planned, the forces of good and evil finally face off, leading to some unexpected revelations.

Archie and the gang band together to save Riverdale from the greatest threat the town has ever faced.