Harry Mudd, complete with the voice of Roger C. Carmel and a bad comb over, basically pulls the same shenanigans here as he did in his first original series episode, "Mudd's Women". (The same writer, Stephen Kandel, penned both that one and this one, as well as "I, Mudd".) This time the focus is on the relationship of Spock and Nurse Chapel, which nicely follows up on threads left by the original series. That said, Carmel and Nimoy don't seem to be too infatuated with the script (which does have its issues) and give sub par performances. This is one of those "in the middle" episodes.
I really enjoyed 'Mudds Passion' just for the fact that it both brings back Mudd, but it also once again explores Christine's love for Spock. She is offered a love potion that actual works, temporarily at least. It has a great alien towards the end of the story when they land on a planet. It looks like mountains, but is actually a couple of huge monsters. Once again, if you enjoy the stories between Spock and Nurse Christine Chapel, then you will enjoy this episode that explores the subject deeper. I, for one, really had fun watching this episode. Great!