Sabrina is obsessing over the whole romantic triangle thing with Harvey and Cassandra. Salem and Chloe each advise her to stop being so insecure and jealous, but she just can't help herself. Sabrina overhears a conversation between Cassandra and Harvey that convinces her that Harvey likes Cassandra more than he likes her. That afternoon, in potion class, she accidentally creates a potion that makes her jealousy come to life - a living embodiment of the old green-eyed monster. Sabrina's rampaging jealousy threatens to destroy the high school and the town, unless she can figure out how to get control of her emotions.