The Invisible Enemy

[metalheadjay]

Certainly one of the most underrated from Tom's era. I've always enjoyed this particular story.

Jay

[Prydonian]

More could have been done with having the Doctor out of control, I feel, but I am quite pleased with how far they went in this serial. The idea of the Doctor being out of control and a possible danger to the companion had not really been done before, at least not since the very early William Hartnell stories, and was something new to the series that made some fans sit up and take notice IMO.