I found this film fascinating, mainly because of the setting of Dr. Ordway's case. Dr. Robert Ordway, eminent New York City psychiatrist, is taking his first vacation in years, and decides to go hunting and fishing for a month. The name of the town Ordway stays in is mentioned - Brook Falls - but the state is not. And there is good reason. Whatever state that was named as the location would have been up in arms about the backwards depiction of its residents.
Several townspeople get ill with "summer complaint" as it is named, and many often die. The town doctor turns out to not really be an M.D. at all, instead, as Ordway finds out by looking at the doc's office wall, the "squire" of the town just gave him a certificate to practice medicine in Brook Falls 30 years before, and he's been feeling his way through ever since! "Doctor" Millerson is more of an herbalist than anything, and doesn't even understand basic chemistry, microbiology, or that a wound needs to be sterilized! Millerson is also resentful of anybody going to the new county clinic for treatment rather than himself. Town barber Ward Beachy becomes very ill and, even though he's been going to the county clinic, Millerson agrees to a house call and gives him some of his "complaint bitters", which is actually a useless yet harmless concoction of herbs.
Now Ordway is boarding with the Millersons since apparently there is no hotel in town, and he has just arrived when the state police and health officials arrive and quarantine the town. Apparently what Millerson calls "summer complaint" is actually typhoid. Once the state officials realize they have the famous Dr. Ordway in their midst they ask him to help out, and of course he agrees. Three people ultimately die during the epidemic, one of them being Beachy. However, a post-mortum shows Beachy did not die of typhoid, instead he was poisoned. Suspicion immediately falls on "Doc" Millerson, since Millerson did treat Beachy and was known to harbor a grudge about Beachy going to the county clinic.
But Ordway just isn't buying it. He figures Millerson may not be a real doctor, but he doesn't figure he's a killer either. Further probing by the good doctor reveals that the married Beachy was a real lady's man, giving possible motives to Beachy's girlfriends, their husbands, maybe even Beachy's own wife. I'll let you watch and see how this all shakes out.
Someone wrote here that the setting is the Blue Ridge Mountains, which is never stated in the film. However, if so, there is even a bigger mystery to solve here. Why would Ordway drive such a long distance for hunting and fishing when upstate New York has the same thing? One possible motive - there appear to be no phones in the town, so nobody back at the office could possibly bother him. Watch this one not just for the mystery, which is engaging, but to see how the urbane Ordway is able to get along with and relate to all kinds of people - a real talent in itself if you think about it.