Richie falls for a con man's ploy when he attempts to find out more about his parents, whom he has never known. The con uses Richie for a place to crash and anything else he can get out of him by pretending to be his father. MacLeod also relives his past in the memories of first becoming immortal and being cast out of his clan by his father.

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.

A beautiful young woman, Felicia Martins, throws herself to her death, only to revive with the realization that she is an Immortal. She seeks out Duncan MacLeod as her mentor, and becomes amorously involved with Richie Ryan. But there is much more to this "ing�nue" than meets the eye. She is in fact a long-time Immortal, engaged in a wily scheme to trap MacLeod and acquire his Quickening. MacLeod must see through her subterfuge in time to protect not only himself, but also Richie.

While visiting the courthouse to clear up Tessa's traffic tickets, MacLeod, Tessa, and Richie are among a group that is taken hostage by a band of men bent on freeing their leader, Slade, from imprisonment. When Slade's demands are not met, he chooses a hostage to sacrifice. MacLeod makes sure that hostage is himself, and returns from the dead to hunt down the gunmen one by one, as the police watch helplessly from outside.

When Tessa is taken by a band of Survivalists who live off the land in the vastness of the Pacific Northwest, MacLeod must call on all of his own skills, honed a hundred and fifty years earlier, when he roamed this same mountain fastness. The leader of these modern day mountain men, Caleb (who is revealed to be an Immortal), falls in love with Tessa, and in the end he and MacLeod battle to the death, axe against sword, against the primitive backdrop of the timeless wilderness.

MacLeod is struck and "killed" by a speeding automobile. When he revives in the hospital, he attracts the attention of a deranged doctor, who kidnaps MacLeod for his research on a miracle cure for trauma. When MacLeod escapes from the doctor, the doctor murders a potential witness and frames MacLeod for it.

Richie Ryan tries to protect an old girlfriend, Nikki, from a band of drug dealers. This puts them both in jeopardy from an Immortal, Voshin, whom MacLeod knows from an adventure during the Second World War when he was trying to smuggle Jewish refugees out of occupied Eastern Europe. Nikki complicates the story by withholding drug money she has stolen from the gang, thinking she can use it to make a better life for her small daughter. Tessa, meanwhile, becomes enamored of the child, raising issues for her and MacLeod.

Seeking revenge for the apparent death of her lover, Walter Reinhardt, Rebecca Lord toys with MacLeod before she attempts to kill him with Reinhardt's sword. Rebecca knows nothing of Immortals or their combat, and she believes MacLeod murdered Reinhardt. Unbeknownst to her, Reinhardt is still alive, and is using Rebecca in a cat and mouse game to draw out MacLeod for their final confrontation.