Episode 46 of "Highlander"
s03e02 Line of Fire

Donna, a girl Richie dated briefly several years ago, returns with her 18-month-old son -- who she claims is Richie's! While MacLeod reminds him that it's impossible, that Immortals are unable to have children, Richie sees this as an opportunity to have the family he never had and never will be able to again. When Kern, an evil Immortal, rides into town, MacLeod is reminded of his own foster son, Kahani. Kahani and his Sioux Indian mother, Little Deer, were massacred over a hundred years ago by U.S. soldiers led by Kern, then a mercenary scout. MacLeod is eager to even the score. When Donna finds Richie's sword and demands to know what it's for, Richie is at a loss to tell her. MacLeod advises Richie that it would be safer and kinder to Donna and the baby to leave them. When his new-found family is threatened by Kern, Richie realizes MacLeod is right. While MacLeod rids the world of the evil Kern, Richie lets go of the only family he'll ever have.