Duncan MacLeod, a clansman of Connor, is being hunted by other immortals and a secret society of mortals known as "The Watchers" who aim to kill him before the time of the gathering. Unlike the immortals, "The Watchers" observe and record without interfering. Immortals can only be killed by decapitation and often live for centuries.
Duncan MacLeod's peaceful existence is disrupted by the return of his kinsman...