Enterprise arrives at Dekendi III for a meeting of the Interspecies Medical Exchange. T'Pol's standing on Enterprise is threatened when it is learned that she has contracted Pa'nar Syndrome, a deadly disease that faces prejudice by Vulcan society. Meanwhile, one of Phlox's wives arrives to install a neutron microscope in Sickbay.

Melinda Page Hamilton (Feezal)
Michael Ensign (Dr. Oratt)
Bob Morrisey (Dr. Strom)
Jeffrey Hayenga (Dr. Yuris)

Lee Spencer (Vulcan Doctor)

• Pa'nar Syndrome is contracted through mind-melds. Tolaris forced T'Pol to mind-meld in "Fusion".
  
• Feezal is Phlox's second wife, who takes a liking to Trip.
  
• Yuris tells the others that T'Pol was forced, so she is allowed to remain.