Terror by Night (1946)

Sherlock Holmes is hired to escort an elderly lady and her son on a train to Scotland, because they are carrying a diamond with them.

The plot is mediocre, but the film is one of the funnier ones in the series. Try not to laugh, for instance, at the dialogue at the luncheon car, which is transcribed on IMDB (it's the one about curry, but they're all good on that page). And there is more, for instance how Holmes keeps pushing Watson into investigating on his own, with interesting results.

Rating: 53