Duncan McLeod is roused from his peaceful existence with the love of this life, Tessa Noel, when he is challenged to Immortal combat by Slan Quince, an Evil Immortal. An old friend and Clansman, Connor MacLeod, comes to try and convince Duncan to once more join the fray in the battle of Good versus Evil. This episode also introduces Richie Ryan, a kid from the streets whom Duncan befriends after catching him breaking into his antique store.

A deadly herbal drug takes the life of Richie's friend, and MacLeod suspects the source of the drug is another Immortal, Kiem Sun, who 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 his old friend must track him down. When it becomes clear that Kiem Sun plans to continue his experiments, MacLeod destroys the remaining sample of the drug.

An Immortal friend of MacLeod's is beheaded in his isolated mountain retreat where he had hoped - like MacLeod - to retire from the fight for a while. A brain-damaged, homeless veteran is charged with the grisly crime, and an attempt is made to link him to the killing of Slan Quince (the villain of episode one, 'The Gathering'), an Evil Immortal whom MacLeod himself had slain in combat. MacLeod must try and clear the innocent man and unravel the mystery of who killed his friend. Here again we get a glimpse of MacLeod's past, in flashbacks set during the American Civil War.