The Avengers (1961)

S1E1 Hot Snow

After the tragic death of his fiancée Peggy at the hands of heroin traffickers, Dr. David Keel is determined to seek justice for her murder. Driven by his grief, he embarks on a mission to find her killers. Along the way, he receives unexpected support from the enigmatic John Steed, who joins him in his pursuit of vengeance.