An ambassador's mental projection harms Troi.
Ambassador Alkar, a diplomat who is renowned for his skill at negotiation, comes aboard the Enterprise for a peace conference. Counselor Troi is attracted to him, but she soon learns that he has a dark secret, a technique that lets him dump his negative emotions into a host. The effects on Troi are alarming, and she begins to age and change.
The story is a thriller about manipulation and emotional abuse, and it is one of the more disturbing stories of the sixth season. Troi must find the strength to resist, and the rest of the crew has to realize that something is seriously wrong. The episode is a showcase for Troi, and her transformation is both haunting and memorable.