With Riverdale High's annual variety show around the corner, Valerie's efforts to help Archie prepare for his big performance lead to some major fallout between her and Josie. Meanwhile, Betty and Jughead's investigation into Jason's death brings them to a home for troubled youth and face-to-face with Polly. Just as her relationship with her mother was on the upswing, an unexpected betrayal sends Veronica spiraling, while Josie deals with her own pressures at home after her overbearing father returns for her performance at the variety show. Finally, Hermoine's first day at Andrew's Construction finds her and Fred growing closer.

As Riverdale High begins rehearsals for its upcoming production of “Carrie the Musical”, the arrival of an ominous letter forces director Kevin to make a difficult decision about the show. Jughead uses his cover as the musical’s documentarian to solve the mystery behind the letter. Meanwhile, tensions between Betty and Veronica continue to escalate just as Alice announces she is joining the musical to spend more time with Betty. Elsewhere, Hiram enacts a devious plan to further drive a wedge between Fred and Archie, while Cheryl channels Carrie White during a showdown with her mother.

When Betty confronts Alice about Gryphons and Gargoyles, Alice has no choice but to come clean about how she, along with a young Fred, FP, Hermoine, Hiram, Sierra, Penelope and Tom, played the game in the early 90’s – and how a shocking mystery has been plaguing them all ever since.

As rehearsals for this year’s musical “Heathers: The Musical” get underway, Cheryl, as queen bee Heather Chandler, channels her own HBIC to deal with a recent fallout. Meanwhile, Betty grows increasingly annoyed by Evelyn’s involvement with the musical – as well as the lives of her friends. Elsewhere, Veronica learns some devastating news about her family, and Archie and Josie make a decision about their future. Lastly, Jughead makes a surprising move against Gladys,

As residents across Riverdale begin receiving more mysterious videotapes on their doorsteps, the seniors of Riverdale High eagerly await their college decision letters. Concerned that the stress may be getting to them, Mrs. Burble, the school's guidance counselor, meets with Betty, Archie, Veronica, Cheryl and Jughead to discuss what's plaguing them.

Refusing to accept what's going on around her, Alice creates an imaginary musical fantasy world in which the Coopers are one big happy family again. But as her mother continues to spiral, Betty does her best to pull her back to reality.

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.

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.

After Principal Featherhead agrees to let Kevin present him with an original musical written by him and Clay, Kevin learns the group might not be as into it as he had hoped. Elsewhere, musical rehearsals prompt Archie to question what he wants in life, while Betty and Veronica confront what's going on between them.

As the town's past secrets start to bubble to the surface, Jughead and the gang are forced to make a difficult decision that will change each of their lives forever.