The U.S.S. Enterprise transports a famous negotiator, Admiral Mark Jameson, to Mordan IV, where several Federation officials have been taken hostage by the planet's governor, Karnas.
Although the crew is excited about having the legendary officer on board, Picard and Dr. Crusher are perplexed by Jameson. When Jameson beams onto the ship it turns out he is a terminally ill man in his eighties. As the voyage progresses, however, Jameson inexplicably begins to look not only healthier, but younger as well! When confronted by Picard, Jameson admits that he has taken an enormous dose of an experimental alien drug to treat his disease, which has resulted in a rapid de-aging process.
Further, the Admiral reveals that Karnas' insistence that he act as a mediator is not coincidental. It seems that 45 years earlier, instead of shrewdly negotiating a similar hostage deal with Karnas, Jameson gave arms to both Karnas and his enemies, thus igniting a devastating40-year civil war. Karnas wants Jameson to return to Mordan ... so Karnas can publicly execute him.
After Jameson leads an aborted rescue mission for the hostages, he collapses in pain. Dr. Crusher reports that the de-aging drug has put an unbearable strain upon his internal organs and that his death is imminent. Seeing the now teenaged Jameson in extraordinary pain, Karnas decides that his revenge has been satisfied.
When Jameson dies, Picard and Karnas negotiate the peaceful release of the hostages.