T'Pol learns the mind meld in Fusion gave her Pa'nar Syndrome, a disease that could make her an outcast among Vulcans.
At an interspecies medical conference, Phlox discovers that T'Pol has Pa'nar Syndrome, a degenerative disorder she contracted during her mind meld in Fusion. Among Vulcans the disease is associated with the minority who practice mind melds, and those with it face discrimination.
T'Pol keeps her condition secret, but Vulcan doctors attending the conference learn of it and threaten her standing. She declines to reveal that the meld was forced on her, which would only reinforce prejudice against those who meld. Archer and Phlox defend her. A comic subplot involves one of Phlox's wives flirting with Tucker. The episode was directed by David Livingston and written by Rick Berman and Brannon Braga.