As Bailey's Comet passes over Rivervale, Cheryl and Nana Rose revisit the tragic stories of the Blossom women through the years. Meanwhile, the once-in-a-lifetime celestial event prompts Cheryl to summon a familiar face to Rivervale - Sabrina Spellman.

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.