Forever Knight.S2E05.Forward into the Past

Forever Knight is a 1992 - 1996 Canadian television series about Nick Knight (Geraint Wyn Davies), an 800-year-old vampire working as a police detective in modern-day Toronto, Ontario. Wracked with guilt for centuries of killing others, he seeks redemption by working as a homicide detective on the night shift while struggling to find a way to become human again.
S2E05 - Forward into the Past
Forty years ago, Nick helped a female friend and her secretary disappear after someone murdered her husband. In the present day, Nick discovers that the secretary is dead, and must find his old friend to prevent her murder.

Aka. Man Lebt nur Zweimal (You Only Live Twice)

Guest Starring:
Stephanie Morgenstern (Young Katherine Barrington)

Cast:
Corinne Conley (Older Katherine Barrington)
Matt Cooke (Young Jeremy Stanton)
Donald Davis (Older Jeremy Stanton)
R.D. Reid (Aristotle)
Carolyn Hay (Ava)
John Freisen (Dectective Norton)
Paul O'Sullivan (Paul Blondell)
Vernon Chapman (George)
Venetia Marie (Young Madelyn Pinchot)
Fran Elliot (Older Madelyn Pinchot)

Written by Michael Levine & John Scheinfeld
Directed by Don McCutcheon