Highlander: The Series - Season 1 - Eps 20: Avenging Angel
When fatal stabbing fails to kill him, Alfred Cahill becomes convinced that he has been chosen by a higher power to wage a crusade against 'perversion', and cuts a bloody path through Paris, murdering prostitutes and pimps, and endangering an old friend of Tessa's who has become a call girl. MacLeod tries to explain Immortality to Cahill, but he can't get through to him, and finally is forced to take his head.
About Highlander: The Series

Title: Highlander: The Series
First Air Date: 1992-10-03
Last Air Date: 1998-05-16
Status: Ended
Rating: 7.394/10 (from 390 votes)
Language: EN
Seasons: 7
Total Episodes: 119
Network: Syndication
Genres: Sci-Fi & Fantasy, Drama, Action & Adventure
Production Companies: Reteitalia, RTL, Gaumont International Television, Amuse Video, Atlantique Productions, Rysher Entertainment, M6 Métropole Télévision, Filmline International, Davis-Panzer Productions, TF1 Films Production, Amuse Soft Entertainment
Synopsis
Duncan MacLeod cannot die -- he is a 400-year-old immortal, who has seen his share of humanity's history. Still, he risks his life in battle against other immortals and tries to save people from harm.
Cast

Adrian Paul
Duncan MacLeod

Jim Byrnes
Joe Dawson