The discovery of the True Cross in Damascus threatens to split the Millennium Group in two.

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 terror 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.

Senator Kinsey manages to shut down all gate activities but SG-1 defies orders and dials the gate coordinates that they got from Daniel's experience in the alternative universe. They soon find themselves inside a Goa'uld mothership heading for Earth.