Rite of Passage (S05E06)

Cassandra, the sole survivor of planet Hanka (episode Singularity), has been adopted by Dr. Fraiser and has been living with her for several years. But during a 16th birthday celebration, a kiss from a new boyfriend causes electricity to surge from Cassandra's body causing lights to explode as she passes out. At SGC, Dr. Fraiser examines Cassandra to find a micovirus in her blood that is causing her body to generate a growing electro-magnetic field. The onset of puberty has evidently triggered the virus causing Cassandra's body to go through changes which may have been started years prior. Seeking answers, SG-1 travels to Cassandra's home planet, where they discover a laboratory in which the Goa'uld Nirrti conducted genetic experiments on the children. Evidently, these experiments are only now manifesting in Cassandra. SG-1 returns home to find that Cassandra's condition has become more dire as her body undergoes more changes. As her heath worsens, SG-1 and Dr. Fraiser fear that they may not have saved Cassandra from the Nirrti's wicked ways after all. (Metro-Goldwyn-Mayer (MGM))