Inspector Oscar Piper (James Gleason) has a twisted new case on his hands when John Carter (Richard Tucker) is found dead in his study by his butler, Kendall (Arthur Aylesworth).

There are several suspicious people in Carter’s circle. Alice Stevens seems to be the last person to have seen Carter alive; her boyfriend, Robert Wilkins, was seen arguing with Carter by a cop; and there’s a mysterious stranger with a French accent whom Kendall overheard speaking with Carter before the crime took place.

The further the investigation moves along, the more questions there are, but Oscar has a secret weapon that may help him crack the case: his girlfriend Hildegarde (ZaSu Pitts), a schoolteacher by day and amateur sleuth by night.

The Plot Thickens 1936
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The Plot Thickens was directed by Ben Holmes. The screenplay was written by Clarence Upson Young and Jack Townley from the story The Riddle of the Dangling Pearl by Stuart Palmer.

It’s no wonder Oscar would have such trouble pinning down the correct suspect when the town’s cops seem to spend more time predicting people’s futures out of astrology booklets than completing thorough patrols!

Luckily for Oscar, the safety of society, and viewers of this film, there’s Hildegarde! She’s a sneaky, smart woman who proves to be much better of a sleuth than Inspector Oscar Piper, even though it’s his profession.

Pitts and Gleason play very well off of one another, and I just adore ZaSu’s take on the character of Hildegarde. She’s intelligent and self-assured, but never big-headed, and possesses plenty of wit.

The Plot Thickens is actually part of a series that began with 1932’s The Penguin Pool Murder. It is the fifth of six Hildegarde Withers films produced in the 1930s! The character would later appear in a 1950s sitcom pilot (now lost) and a 1972 TV movie, too.

Edna May Oliver originated the character of Hildegarde on-screen. I can’t speak to her performance, as the only other film in the series I’ve seen is the fourth, 1936’s Murder on the Bridle Path. That one starred Helen Broderick as Hildegarde, and I, unfortunately, found it dull and slow.

The Plot Thickens 1936 still
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I had a lot more fun with this film than I did with Bridle Path, thanks in very large part to the great ZaSu Pitts! She’s not only great to watch on her own, but brings out more energy from Gleason, making them delightful to watch as a pair.

I would recommend The Plot Thickens to fellow “amateur sleuth” mystery fans. It’s a quick and very enjoyable watch. I don’t think it’s necessary to watch the entire series in order, though I am now interested in seeking out Forty Naughty Girls (1937) — the final film in the series, which also starred ZaSu.