In the best movies of the thirties, the stars are glib (in the best way) and glamorous. Libeled Lady is blessed with a clever script that serves up fastballs that the cast handles adroitly. And I have to credit the amazing wardrobe by Dolly Tree, made all the more remarkable as she was responsible for the wardrobes of 23 films in 1936. Loy's wardrobe, in particular, is impeccable.
This was the 5th in the series of William Powell/Myrna Loy pairings. They were cranking them out at a rate of about 2 per year during this period, so you might think that the chemistry between them would be stale or formulaic. But in Libeled Lady, the chemistry is fresh and the relationship between their characters is not just another Thin Man performance.
Then there are Spencer Tracy and Jean Harlow. Tracy is adept at the machine-gun delivery required by this (screwball) comedy, and Harlow just shines, showing more depth of character and emotion than she is sometimes given credit for. After Libeled Lady, she only acted in two films, so the screen never saw what greater depths of performance she might have achieved. (She died of uremic poisoning during the filming of Saratoga Trunk)
The plot involves a newspaperman (Powell), good at the con, who ingratiates himself to a wealthy young woman (Loy) and her father in order to set her up for a blackmail situation. She suspects his motives, but he manages to pull her in. Plenty of plot curves ensue, adding humor and more character development.
I particularly liked the fishing scene. Without much dialogue it advances the plot, provides some laughs and shows that Dolly Tree can even make Myrna Loy look sexy in fishing gear.