Colonel March investigates when Dr Ivy tells him that a 12 year old boy, distraught over his father's death. A renowned scientist is trying to kill his stepfather to be.
Andrew Barton hears the voice of his late father when he visits the bust in his study. The voice tells Andrew to kill Harold Hartley the family friend who is engaged to his mother.
Hartley has already been injured from an earlier attempt but is surprisingly forgiving towards Andrew.
Colonel March acts rather cold regarding his feelings towards children. It is all a facade.
Once Colonel March hears the voice ordering Andrew to make another attempt on Harold's life. It becomes clear just who the culprit might be even though the motive might not be.
An enjoyable enough episode with Colonel March once again displaying his cunning to reveal the culprit.