It's been a while since David had an outright love interest. I still think David shouldn't be fooling around with women's hearts knowing all the while that he can't stay in one place for too long, but the fact that it hasn't happened much this season makes this occasion more acceptable. More importantly, this episode's damsel is more compelling than most.
See, Nancy is the "psychic" of a traveling circus sideshow, and the way she plies her craft is particularly intriguing. You have to watch the episode to really appreciate it. Her character in general is blessed with only average development but excellent writing. Except, well... During her act, Nancy not only "divines" her audience's secret problems, she tries to offer them solutions in the manner of an armchair psychologist. It's a sweet idea, and I appreciate the probably intentional parallel to the way David helps people, but I still feel like she's overstepping her bounds. She may have deduced a few facts about her audience members, but she certainly doesn't know them well enough to give them qualified advice.
The conflict comes from a stalker who blames Nancy for his son's suicide. It's implied that the boy was actually driven to suicide by the fundamentalist Christian upbringing his father gave him, and the plot in general leans uncomfortably towards a "Christians are evil" message, saved only by David quoting Psalm 145 in an attempt to persuade the stalker off the path of vengeance. Bixby's recitation of the passage is wonderfully eloquent.
While I have quibbles with both Nancy's character and her stalker, both aspects of the plot are captivating. It's not a perfect episode, but it appealed to me.