Sunspot activity causes molecular instability for the witches present in the moral realm: Zelda's left arm attaches itself to Hilda, who is auditioning to become part of a classical trio, and a black hole forms in their kitchen sink. Because Sabrina is half mortal, they are not sure how she will be affected. Participating in a charity drive to collect food for the homeless, Sabrina is at first relieved to experience no worse symptoms than temporary hair loss; but when she protests at Libby's conniving with Mr. Kraft to turn the drive into a competition, things take a turn for the worse: Sabrina and Libby bump into each other and exchange personalities. While Libby become sweetness and light, Sabrina becomes a teenage bitch who soon rules the school and - with the connivance of Salem - begins to plot world domination. When she is arrested and brought to trial, it's up to a repentant Salem to find a way to save her.