Antonym of "highlight" (as in highlight of the movie)
Solution 1:
I would most likely say low point.
Solution 2:
Nadir is the opposite of zenith, but could conceivably be used, as in The nadir comes when the leading actor tries to sing.
Solution 3:
Why don't you use lowlight?
Solution 4:
How about a low ebb?
Solution 5:
I would go for nadir, but I have one problem with it: a highlight in the movie example can be other things (a theme, a broader message), too, whereas nadir is restricted to meaning a point in the story line, or a particular scene in the movie