Steed and Emma's new friend has a secret agenda. It seems he is the brother of the late Dr. Clement Armstrong... creator of the deadly Cybernauts... and is bent on avenging his brother's death!

An excellent guest star, Peter Cushing is wasted on a rather weak script. To me, I think The Avengers is far too intelligent of a show to have to resort to the silly "mind-control" plot. If this episode could be combined with its sequel, The Last of the Cybernauts...?, substituting Cushing's character for Felix Kane and using Armstrong's original assistant, Benson (played by Frederick Jaeger), it might have been something.

It is never explained why Beresford and Armstrong are brothers, yet have different last names.

As Steed raises the bronze bust of Emma, Steed's watch is shown in a close-up, then later in a black and white photo presumably taken at that moment in time. In the photo, however, Steed's watch is on backwards (the stem is pointing towards his arm instead of his hand), his shirt cuff is different, and the time is wrong.

Also, notice that Steed leaves Beresford's place in a gray suit, rushes directly over to the attorney's home and is suddenly wearing a dark blue suit when he is clobbered by the Cybernaut?

  - Courtesy of David K. Smith / The Avengers Forever

If Doctors Neville and Chadwick require specific information like the connectivity of Steed and Emma's skin and their epidermal resistance (necessitating the need for the bronze bust) in order to customize their invention specifically to their victims, how is it that during the test it works so well on their unexpected human guinea pig, Dr. Garnett?