Before I get into the synopsis for tonight's episode, I'd like to give props to whomever decided to use this title for the episode. Return To Riverdale was also the alternate title for the made for TV movie/pilot for a show that never came to be that aired in the 90s.
Anyway, according to TV Guide this week's episode is as follows:
"Despite Betty being overwhelmed with overseeing Homecoming and Reunion weekend, Alice wants her to help with the Jason Blossom investigation. And Betty is not happy to learn that Veronica and Archie are helping Alice. Meanwhile, Jughead considers giving his father another chance after seeing him try to clean up his act; Polly and Cheryl both decide to go to Homecoming in Jason's honor; and Fred and Mary attend the Homecoming dance, leaving him to possibly reconsider the divorce."