- Richie's friend dies of an overdose of a herbal drug and MacLeod suspects the source of the drug is another Immortal, Kiem Sun. Sun has has long sought to perfect such a drug and remove its lethal side effects for the betterment of mankind. But a disciple of Kiem Sun's is using the drug for his own gain, and MacLeod and Sun must track him down. When it becomes clear that Kiem Sun plans to continue his experiments despite the dangers, MacLeod destroys the remaining sample of the drug.
Although Kiem Sun starts out developing the drug to help mankind, he ultimately wishes to use it for his own gain by using mortals to help him triumph in the Gathering.
This highlights two important points:
(1) The classic Sword & Sorcery conflict where the sword represents what is noble and righteous and sorcery represents what is evil and trecherous.
(2) Technology as "masculine" sorcery. Though sorcery is traditionally associated with feminine qualities, technology is often depicted as a masculine form of sorcery.
I take away from this that one of the key values of Sword & Sorcery is honesty.