Tonton Streaming Highlander: The Series (1992) S1E4 - Innocent Man

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.