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.

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.

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.

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.

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.

Tessa witnesses the murder of a painter, Anne Wheeler, but the absence of a body leads everyone but MacLeod to doubt her story. MacLeod supports Tessa in her quest to obtain justice for Anne. It develops that Anne was killed by her Immortal ex-lover, to keep her from revealing his secret. After Tessa is taken to a police safe house, MacLeod realizes that the killer is in fact the Chief of Detectives, and he must rescue Tessa and bring justice to Anne's killer.

An Evil Immortal, Kuyler, has hired himself out down through time as an assassin -- the most successful killer in all of history. He strikes again in modern day Paris using his signature disguise as a mime. A French Police Detective, LeBrun, suspects that Duncan MacLeod is connected to Kuyler, but of course he cannot imagine that Kuyler once killed an eighteenth-century baron under MacLeod's protection. When LeBrun is wounded protecting Tessa from Kuyler's men, MacLeod confronts the Immortal assassin and puts an end to his centuries-old reign of terror.